The junta is battling widespread armed opposition to its 2021 coup and its soldiers are accused of bloody rampages and using air and artillery strikes to punish civilian communities.

"They bombed at two areas in Namhkam" town on Friday around 1:00 am local time (1830 GMT), Lway Yay Oo of the Ta'ang National Liberation Army (TNLA) said.

The strikes killed 11 and wounded 11, she said, adding that the office of a local political party had been damaged.

The dead were five men, four women and two children, she said.

Namhkam is around five kilometres (three miles) from the border with China's Yunnan province, with TNLA fighters claiming control of the town following weeks of fighting last year.

Images on social media showed people sifting through rubble and carrying a young person who appeared to be wounded.

One video showed several destroyed buildings. AFP reporters geolocated that video to a site in Namhkam and said it had not appeared online before.

One resident said she had seen 13 wounded people in the local hospital.

"I heard they will hold funerals this evening," she told AFP, asking for anonymity for security reasons.

The TNLA had warned residents of the danger of further airstrikes and said people would be allowed to leave the town for safety, she added.

AFP was unable to reach a junta spokesman for comment.

Since last year the military has lost swaths of territory near the border with China in northern Shan state to an alliance of armed ethnic minority groups and "People's Defence Forces" battling to overturn its coup.

The groups have seized a regional military command and taken control of lucrative border trade crossings, prompting rare public criticism by military supporters of the junta's top leadership.

Earlier this week junta chief Min Aung Hlaing warned civilians in territory held by ethnic minority armed groups to prepare for military counterattacks, state media reported.

The junta also announced this week that it had declared the TNLA a "terrorist" organisation.

Those found supporting or contacting the TNLA and two other ethnic minority armed groups, the Arakan Army (AA), Myanmar National Democratic Alliance Army (MNDAA), can now face legal action.

Myanmar has been in turmoil since the military deposed Aung San Suu Kyi's government in 2021 and launched a crackdown that sparked an armed uprising.

Conflict since the coup has forced more than 2.7 million people to flee their homes, according to the United Nations.