Myanmar's military seized power in a 2021 coup, sparking a civil war pitching it against pro-democracy guerrillas and resurgent ethnic armed groups that have long been active in the Southeast Asian country's fringes.

Most combat is confined to the countryside and smaller settlements, although sporadic grenade and gun attacks on police and junta-affiliated targets are regularly reported in the largest city Yangon.

A source close to the military said former general and Cambodia ambassador Cho Tun Aung "was shot and killed" outside his Yangon home around 8:30 am (0200 GMT) as he gave alms to monks collecting donations.

"He used to donate meals every morning," the source said, speaking on condition of anonymity. "The shooters used this opportunity to assassinate him."

A military officer, also speaking on condition of anonymity, confirmed Cho Tun Aung had been shot and killed without providing further details.

AFP was not immediately able to verify their claims and a junta spokesman could not be reached for comment.

The attack was claimed by the Golden Valley Warriors, a little-known group that said Cho Tun Aung had been a confidant of junta chief Min Aung Hlaing and was teaching at a defence academy in his retirement.

"Our Golden Valley Warriors team conducted the shooting after collecting and verifying information for a long time," the statement said.

The junta has suffered stinging territorial setbacks in recent months but analysts say it is far from defeat, with a powerful air force supplied with Russian jets and military backing from China.

Ethnic armed groups have proven the military's most capable opponents but often have ambitions limited to their own areas, while pro-democracy guerrillas are scattered and poorly coordinated.