On 5 March, following the capture of the Vietnamese capital of Lạng Sơn, as well as what analyst described as "other military successes along the 500 mile front", the Chinese forces then declared that they had “attained the goals set for them” in the 17-day border war and that they were withdrawing troops from Vietnam.

Another force from the 42nd (otherwise the 129th Division[13]) would be sent through Highway 4 to join with friendly units north of Lạng Sơn, thus enabling the transfer of troops between the two fronts, as well as blocking enemy reinforcements from Thái Nguyên.

[14] However, it had failed to meet the 24-hour schedule to obtain the objectives around Cao Bằng, due to difficult terrain and frequent Vietnamese ambushes.

[14] According to report from the Vietnamese side, they had severely mauled four Chinese battalions and destroyed scores of enemy tanks and vehicles after the first three days of fighting in the province.

Instead of waiting for the 41st Army to break through enemy defense from the north, General Xu Shiyou, the overall commander of the Chinese campaign in Vietnam, ordered an immediate assault on the city.

On the same day, Vietnamese forces staged counter-attacks against the occupied towns of Quảng Uyên and Trà Lĩnh, where Chinese control had not been restored until 2 and 3 March respectively.

For instance, it took the PLA a whole day searching for VPA regulars in the Ke Map Nua area, 3 km north of Cao Bằng, without any results.

[20] With the exception of Sóc Giang, most of the clashes were fought against Vietnamese militia and citizen-soldiers, who had inflicted heavy losses on Chinese troops and held off their invasion.

Retreating Chinese forces adopted a scorched earth policy, destroying infrastructure, industrial facilities, and population centers.

In its course, the Chinese were accused of various war crimes by Vietnamese authorities, such as the Tong Chup massacre at the village of Tổng Chúp, Hòa An District on 9 March, in which troopers of the PLA 42nd Army had reportedly executed 43 civilians by axes.

Allegations remain largely unverifiable and unbenknowest to the international community as no Western correspondents were able to access the Sino-Vietnamese border region when fighting was occurring.