Myanmar's military shelled a town in western Rakhine state and used helicopters to attack fighters from an ethnic minority there on Thursday, residents and local media said.
Arakan Army (AA) fighters have launched attacks on security forces across Rakhine this week, opening another front as the military battles opponents in the north and east.
AA fighters had taken "complete control" of the town of Pauktaw, 25 kilometres (16 miles) east of the state capital Sittwe, a resident told AFP after requesting anonymity for security reasons.
The military was shelling the town and helicopters were shooting at its police station, which was now occupied by AA fighters, they said.
The resident reported hearing almost continuous gunfire and artillery shelling and said many in the town had fled.
Around 30 policemen in Pauktaw had surrendered to the AA on Wednesday, another resident said, also requesting anonymity out of fear for their safety.
A Myanmar navy ship was also approaching the town from the Kywegu river, local media reported.
Three Rohingya were killed by artillery shelling during fighting between the AA and the military on Tuesday night in Minbya township in Rakhine's north, a local Rohingya leader told AFP on Thursday.
"Fighting has been ongoing since then," the Rohingya leader said. "Many Rohingyas need help for food and places to hide."
AA fighters are also battling the junta across northern Shan state as part of an alliance of ethnic minority groups that has seized towns and blocked vital trade routes to China.
A ceasefire between the junta and the AA in Rakhine had held until this week, despite the ongoing clashes in the north.
The AA has for years fought a war for the autonomy of the state's ethnic Rakhine population in their home near the Bangladesh border.
Clashes between the AA and the military in 2019 displaced more than 200,000 people across Rakhine state, home to around one million people.