Shortly after the invasion of the 1st Route of the Angolan Army, the 2nd Route Army, with the cooperation of tanks, broke through the Snu Line of the Khmer Army in three directions and continued to invade north along Highway 13.

The Khmer 117th and 280th Divisions made a stubborn resistance, but were outnumbered and quickly retreated westward. The ANA captured the Mekong-lit city of Kratie in December. After that, the Anjun army pursued the victory, developed an offensive along Highway 6 in depth, and in January 1979, successively captured Kampong Thom, Sisophon and other towns.

At the same time, the 3rd Route of the Anjun Army advanced westward from Krek. Because the Angolan army instigated the defection of Han Samlin, the commander of the 4th Division of the 3rd Military Region of the former Khmer Army, the Angolan army soldiers successfully advanced to Dong Libe, an important ferry crossing of the Mekong River, in January 1979, and crossed the river to besiege Kampong Cham.

After that, part of the Anjun army moved south, cooperated with the Fourth Route Force to attack Angkor, and the main force advanced westward along Highway 5 at full speed, and occupied important towns such as Kampong Chhnang and Battambang in January 1979.

The main Angolan Army's Fourth Attack Force launched its offensive two days later, on 27 December, with the aim of successfully diverting the attention of the Khmer army and capturing Angkor in the first battle.

The attacking force was divided into two routes, one along Highway 1, and due to the heavy deployment of troops in this direction by the Khmer army (a total of 5 divisions), the development of the Angol army was not very smooth, and it was not until early January 1979 that the Khmer army captured the front town of Svay Rieng. The Angolan army moved north along the Mekong River, penetrating the provinces of Prey Veng and Kandal, advancing to Nai Raung on 4 January, and then rapidly advancing to the Sam Lung Thong area, about 40 km east of Angkor.

The 5th Road, with the support of the Air Force, advanced north along Highways 2 and 3. The Khmer army also deployed five divisions in this area, but it was quickly broken through by the Ana army due to the wide frontage of its defense. After that, the Anjun army was like a bullfight, and launched an all-out attack to the north and west, and on January 5, 1979, it successively occupied Takeo, Gongba and other places. And with a force to break into the southwest of Angkor, cut off Highway 4, cut off the foreign aid channel from Angkor to Sihanoukville. By this point, the Angolan army had largely occupied the area east of the Mekong River.

At the beginning of January 1979, while continuing to consolidate the occupied areas and pursue the Cambodian troops, the Angolan army approached Angkor from the east, west and south, cutting off all access to Angkor except Highway 5, forming a semi-arc encirclement of Angkor.

Angkor, the capital of Khmer, is located at the confluence of the Tonle Sap Lake and the Mekong River, and is the political, economic, financial, cultural and transportation hub of the Khmer. The purpose of Annan's war of aggression against Cambodia was to occupy Angkor and install a pro-Vietnamese puppet regime. The Anjun army is determined to win, so it launches round after round of crazy attacks. The Cambodian troops stationed in Angkor knew that they were outnumbered and took the initiative to withdraw from Angkor, and Angkor fell.

Then, the Angolan army with 6 armored brigades and infantry organized into a number of assault clusters, from three directions to the western part of Cambodia, without the effective resistance of the Khmer army, along the highway rapid advance, the daily advance speed of 40 ~ 100 kilometers, occupy Cambodia's main towns and communication lines.

To the southwest of Angkor, the An army advanced towards Kampong Son in three directions. All the way south along Route 4, all the way west, all the way (1 Marine Brigade), with the support of the Vietnamese 171st Fleet, landed from Ream and took control of Sihanoukville on January 10. By 12 January, the Angolan army had occupied the entire Khmer town and a large area.

In this battle, the Khmer army suffered heavy losses, killing and capturing 13,000 people.

Due to the underestimation of the large-scale invasion of the Angolan army before the war, the Cambodian troops lost their defensive positions on the front line, completely collapsed their defensive formations, and suffered great losses in their vitality, and were unable to prevent the Angolan troops from advancing straight in. Under such difficult circumstances, the highest command of the Khmer army decided to move to the mountainous areas on the border between Khmer and Siam in the west, and to disperse the resistance.

Taking advantage of the gap between the Angolan army's high-speed advance on the communication line, the Khmer army regrouped the troops scattered in the rear of the Angolan army and moved northwest along Highway 5, thus preserving part of the backbone and gaining a foothold in the western border area, laying the foundation for the future war of resistance against Vietnam and national salvation.

After the Angolan army occupied Angkor, while establishing and supporting the puppet regime of Han Samlin, it stepped up its efforts to "clean up" and "sweep up" the resistance forces of the people and Cambodia. In March ~ May 1979, the Angolan army dispatched 5 divisions to capture Temobo, Poipet, Pailin, Dasheng and other places in the border areas of Cambodia and Thailand, and carried out "encirclement and suppression" of the Khmer National Army base areas in the areas north of Mount Machen, Mount Melai and Sisophon.

From mid-September, the Angolan army began its second "dry season sweep". First of all, the troops of five divisions were used to "clean up" the central and northeastern regions of Cambodia, but because the Khmer Nationalist Army was reduced to pieces, the Angolan Army was swept into the air, and there was nothing to gain except to destroy and occupy part of the Khmer Nationalist Army's base areas and logistics warehouses.

Since October, the focus has been on the northwestern border areas of the Khmer. In November, it occupied some villages east and south of Mount Melay, and continued shelling and incursions into Siam territory.

In order to annex Khmer for a long time, the Annam authorities transferred a large number of cadres and backbone cadres from the country to assist the Cambodian puppet government in establishing puppet regimes at all levels and building up armed forces. It has also stepped up immigration to Cambodia, and about 700,000 Annam people have moved to settle in the Khmer. In order to "legitimize" the invasion of Cambodia, Annan successively signed a "friendship treaty," a "border agreement," and a "aviation agreement" with the Cambodian puppet government.

In order to encircle, suppress, and blockade the strength of the various Khmer factions, the Annam people transferred the methods used by the Americans against them to the Khmer battlefield to deal with the Khmer people. While establishing puppet regimes at all levels, they also established "strategic villages" and "fortress villages" to exercise strict control over the residents of the villages.

But the wishful thinking of the Annan authorities failed. The invading Cambodian army soon fell into a vast sea of armed strength of various Khmer factions, and they used various forms of guerrilla warfare, such as attacks and ambushes, to bravely resist the invading enemy in the western mountainous base areas.

Among the Khmer anti-Vietnamese forces, there are three factions whose armed forces are the most famous.

The Khmer National Army, whose predecessor was the government army. When the Angola army invaded, the Khmer government had a total of 120,000 armed forces. After the troops were dispersed, the remnants moved to the jungle areas of the Khmer-Siam border to engage in guerrilla warfare. In 1979, when the troops were reorganized during the rainy season, the number was about 30,000. In December of the same year, it was renamed the Khmer National Army. Its leader is Song Cheng, the former deputy prime minister in charge of national defense affairs in the Cambodian government.

The Sihanouk Nationalist Army is an armed force under Prince Norodom Sihanouk. It is made up of "free Khmer" elements and some former soldiers from the Lon Nol government, with a strength of about 10,000 troops, and is based on the Khmer-Siam border in northern Khmer. The force received military assistance from China, Siam, Singapore and Malaysia.

The Khmer People's Liberation Army is an armed force led by Song Shuang. After Annam invaded and occupied Angkor, with the support of China, Thailand, the United States and other countries, Song Shuang announced the formation of the "Khmer People's Liberation Army" on the Khmer-Siam border in March 1979, with a force of about 12,000 troops, based in Appi village on the Siam side of the northwestern border of Cambodia.

In order to establish a broad united front, put national interests first, and jointly deal with the invading enemy, the three Khmer factions signed the Declaration on the Establishment of the Khmer Coalition Government in Kuala Lumpur, the capital of Malaysia, on June 22, 1982, calling for "mobilizing all forces and forces to fight together to liberate the Khmer from the Annam invaders in order to restore the motherland as a sovereign and independent state." ”

Later, the establishment of the Khmer-Cambodia coalition government was announced, and since then, the three armed forces of the Khmer have joined forces to jointly fight the war against Vietnam.

Since the end of March last year, the Angolan army has launched a new offensive in the western border area of Cambodia and has repeatedly invaded Siam, causing tension on the Khmer-Siam border. The main purpose of the ANA's actions is to exert pressure on Siam and other ASEAN countries to compromise with Vietnam on the Khmer issue, and at the same time, to further weaken the strength of the anti-Vietnamese armed forces and improve the situation on the battlefield. But Siam took a tough stance and fought back resolutely against the invasion of the Anjun army.

Since the beginning of last year's dry season, the Khmer anti-Vietnamese forces have actively carried out sabotage activities along Highway 5 and 6 to expand the guerrilla zone along the Tonle Sap Lake. In line with this, in the northwest of Koh Kong, the border of Pailin, and the southern part of Sisophon, the Khmer anti-Vietnamese forces took the initiative to attack the Angolan army, uprooting some strongholds of the Angolan army, and destroying some of the enemy's vital strength.

In mid-December, two main Minkhmer-Cambodian forces stationed in the northern Khmer-Siam border region sent advance troops to advance south along both sides of Highway 12. From late January to early February 1984, they successively attacked the provincial capitals of Kampong Dong and Siem Reap and the surrounding Anjun strongholds.

In the middle of the night on 14 April this year, a unit of the Angolan Army, supported by tanks and artillery, suddenly attacked Appi Village, the headquarters of the Khmer People's National Liberation Front led by Song Shuang, the Coalition Government of Cambodia and Cambodia. The Khmer People's Liberation Army (PLA) has built deep and wide trenches and strong bunkers around the base, which are easy to defend and difficult to attack.

When the Angolan army attacked, the Cambodian National Liberation Army quickly put up stubborn resistance around the camp. At 4 a.m. on the 15th, the Angolan army concentrated its firepower to storm the position of Appi Lake, and at 7 o'clock the Angolan army captured the position, and the fighters of the Cambodian National Liberation Army took the initiative to retreat to the second line of defense. At noon on the 15th, the Anban army surrounded Appi Village in three ways. The Angolan army special forces team reached Appi Village, and then the infantry carrying T-54 tanks also reached Appi Village.

After a short preparation of firepower, the Angolan army launched a fierce charge. The Cambodian People's Liberation Army (PLA), which defended the village of Appi, took advantage of the familiar terrain and the pre-set fortifications to repel wave after wave of attacks by the Anbi army. In front of the position, the corpses of the An army were all over the field, their spirit was greatly frustrated, and they fled in embarrassment.

At present, the Anjun Army has been mired in the vast sea of the Khmer people's war and cannot extricate itself. Although the Anjun army is still in the offensive phase and has an absolute advantage, the Khmer resistance is difficult to resist and is generally weak. However, the momentum of its offensive is also at the end of its strong crossbow, but its resistance is getting stronger and stronger with international support.

After Yang Mingtao's briefing, he suddenly looked at everyone, "The current situation in Khmer is already in a strategic equilibrium, and no one can help anyone in the short term!" As one of the core contents of the South Asia strategy, if we add a little external force to the side of the Khmer's resistance, the balance will tilt, and the Khmer will become a shackle and a hell for the Annamite people......"