An alliance of Myanmar ethnic armed groups has accused the junta of repeatedly violating a China-brokered ceasefire in the north of the country this month and causing civilian casualties.
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 Ta'ang National Liberation Army (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.
Junta troops launched an air strike on Wednesday on territory the TNLA holds near the ruby and gem-mining hub of Mogok, the group said.
"In this incident, one civilian was killed and 3 wounded including a 10-year-old child," the TNLA said in a statement posted to the alliance's Telegram channel on Wednesday.
Junta troops had also launched a drone attack on Tuesday that killed one TNLA member and seriously wounded four others, the group said.
The attacks were the latest violation this month by the junta, which the TNLA said had shelled its positions and cut roads and restricted the flow of goods to TNLA-controlled towns.
Junta spokesman Zaw Min Tun accused the TNLA of being the "main group behind disturbances" in Shan state.
TNLA fighters had fought alongside local "People's Defence Forces" in recent fighting near the town of Pyin Oo Lwin, he said.
Dozens of PDFs have sprung up since the 2021 coup and have surprised the military with their effectiveness, according to analysts.
The "Three Brotherhood Alliance" launched a surprise offensive across northern Myanmar in October last year, seizing several towns and lucrative border hubs that are vital for trade with China, dealing a blow to the cash-strapped and isolated junta.
Border trade with China during April-May was down by almost a third compared to the same period last year, junta-controlled media reported last week.
China hosted follow-up peace talks last month between the military and the alliance in the city of Kunming.
A source close to the MNDAA told AFP that no substantial progress had been made and the two sides would meet again in the future.
Myanmar's borderlands are home to a plethora of ethnic armed groups, many of whom have battled the military since independence from Britain in 1948 over autonomy and control of lucrative resources.
Fighting in Shan state has calmed but the AA has launched its own offensive in western Rakhine state, where it says it is battling for more autonomy for the ethnic Rakhine population.
Its fighters have seized territory along the border with India and Bangladesh, piling further pressure on the junta as it battles opponents elsewhere across the Southeast Asian country.