A destroyer, frigate and a supply vessel carrying hundreds of sailors arrived at Thilawa port on Monday ahead of "naval security exercises between Myanmar and China", the junta's information team said.

It did not give details about the drills or when they would begin but state media reported the Chinese "naval task force" was 700 sailors strong.

Beijing is a major ally and arms supplier of Myanmar's junta and has refused to label its 2021 power grab a coup.

Relations have been tested recently as the junta battles an alliance of ethnic minority groups across a swathe of territory near the China border.

The junta has said the groups are using drones made in China in their offensive that has seized trade hubs and dozens of military outposts in northern Shan state.

Earlier this month protesters gathered at a rare demonstration in Yangon to accuse China of backing the armed groups, in what analysts say was a move sanctioned by junta authorities.

Beijing has expressed "strong dissatisfaction" over the clashes in northern Shan state, home to oil and gas pipelines that supply China and a planned billion-dollar railway link.

China has said the fighting has caused Chinese "casualties" on its side of the border, without giving details.

Beijing has also been frustrated by the junta's failure to crack down on online scam compounds in Myanmar's lawless borderlands that target Chinese citizens.

On Saturday, China kicked off military exercises near the Myanmar border, days after an attack on a compound in the Myanmar border hub of Muse destroyed more than one hundred vehicles.

The offensive launched last month by an alliance of three ethnic minority armed groups has galvanised other opponents of the junta.

Clashes have spread to the east and the west of the country and forced nearly 335,000 people to flee their homes, according to the United Nations.