China's military will begin "combat training activities" from Saturday on its side of the border with Myanmar, it said on social media, a day after a convoy of trucks carrying goods into the neighbouring Southeast Asian nation went up in flames.

The incident, which Myanmar state media called an insurgent attack, came amid insecurity concerns in China, whose envoy met top officials in Myanmar's capital for talks on border stability after recent signs of rare strain in their ties.

The training aims to "test the rapid maneuverability, border sealing and fire strike capabilities of theatre troops," the Southern Theatre Command, one of five in China's People's Liberation Army, said on the WeChat messaging app.

The brief statement gave no details of timing or numbers of troops.

Myanmar was told of the drills, military junta spokesman Zaw Min Tun said, adding that they aimed to "maintain stability and peace" near the border, and did not undermine China's policy of non-interference in Myanmar's internal affairs.

"The military tie between China and Myanmar is firm and collaboration between both armies is friendly and building up," he said in his post on state-run social media.

Friday's fire in the town of Muse came as Myanmar's military has lost control of several towns and military outposts in the northeast and elsewhere as it battles the biggest co-ordinated offensive it has faced since seizing power in a 2021 coup.

The surge in fighting has displaced more than 2 million people in Myanmar, the United Nations says.