At least five government and security officials were killed and 11 other policemen injured when a bomb ripped through a government compound in the Myanmar border hub of Myawady, sources said Monday.

The town on the border with Thailand has seen sporadic clashes between the military and anti-junta fighters since a coup in 2021 plunged the country into turmoil.

Early Sunday evening two "drop bombs" fell into a compound containing the district police office and general administration office, a military source told the Agence France-Presse (AFP).

As officials took "security measures" after the blasts, another two bombs were dropped, killing five and wounding 11, they said, requesting anonymity as they were not authorized to talk to the media.

The dead included a military officer, two police officers and two officials from the administration department, they said.

Eleven "junior and senior" police officers were wounded, five critically, they added.

A local police source who also requested anonymity confirmed the incident and casualty figures.

Neither source said who was responsible for the attack.

The junta said "some security members and government staff" were wounded in the attack, without giving a figure.

It blamed the anti-coup "People's Defence Forces" and the Karen National Liberation Army, an established ethnic rebel group that has fought the military for decades.

Anti-junta fighters battling to overturn the coup that deposed Aung San Suu Kyi's government have used commercial drones for surveillance and also as crude bomb-dropping devices.

A Myawady resident who did not want to be named told AFP they heard two blasts in the town, which abuts the Thai province of Tak, on Sunday evening.

Since the coup, the KNLA and PDF groups have clashed sporadically with the military in Myawady town and its surrounds in Karen state, sending tens of thousands fleeing into Thailand.