The attack, shortly before 3 pm (0830 GMT), comes as the junta battles widespread armed opposition to its 2021 coup and its soldiers accused of bloody rampages and using air and artillery strikes to punish civilian communities.

"They were civilians who came to drink tea and were sitting at the shop," Lway Yay Oo, a spokesperson for the Ta'ang National Liberation Army (TNLA) said.

At least four civilians were wounded and were receiving treatment in a hospital, she said.

Local media also reported that 11 people had died, but said many were injured in an army air attack on Lansan tea shop.

The attack is the latest violation by the junta in recent months of a China-brokered ceasefire signed early this year.

Beijing brokered a truce between the junta and the "Three Brotherhood Alliance" in January after months of fighting that displaced more than half a million people near China's southern border.

The ceasefire allowed the alliance -- made up of the TNLA, the Myanmar National Democratic Alliance Army (MNDAA) and the Arakan Army (AA) -- to hold swaths of territory it had seized in northern Shan state.

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.

Last week junta chief Min Aung Hlaing met with China's Premier Li Qiang in the southwestern Chinese city of Kunming where he said that the military was ready for peace if armed groups would engage, according to Myanmar state media.

China has been a major arms supplier to the junta and provided Myanmar with political backing even as other countries shun the generals over their brutal crackdown on dissent.

But Beijing is concerned about the chaos unfolding on its doorstep.

Since last year the military has lost swathes of territory near the border with China in 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.