At least 26,000 people were displaced after ethnic violence by Myanmar's military, according to the U.N.

Ongoing clashes between the Arakan Army (AA) and the military "have resulted in the displacement of 26,175 people" across Rakhine, the United Nations Office for the Coordination of Humanitarian Affairs said in an update.

AA fighters launched attacks on security forces in Rakhine and neighboring Chin state on Monday, ending a shaky cease-fire and opening another front as the military battles opponents in the north and east.

UNOCHA said at least 11 people had been killed in military shelling of AA positions since Monday.

On Thursday junta troops shelled the town of Pauktaw, 16 miles (25 kilometers) west of the state capital Sittwe, and shot at it from helicopters after AA fighters briefly seized the police station, residents told AFP.

The military took control of the town later in the day, and on Friday local media cited residents saying that around 50 people had been detained and an unknown number were feared dead.

UNOCHA said 19,000 people had been displaced from Pauktaw.

"Virtually all" roads and waterways connecting Rakhine townships have been blocked, UNOCHA said, adding most humanitarian activities in affected townships had been suspended.

It added more than 100 people had reportedly been detained by junta authorities since the renewed clashes.

For years the AA has fought a war for the autonomy of the state's ethnic Rakhine population in their home near the border with Bangladesh

Since last month AA fighters, in alliance with two other armed ethnic minority groups, have been battling the junta across a swathe of northern Shan state near the border with China.

The alliance, which includes the Myanmar National Democratic Alliance Army (MNDAA) and the Ta'ang National Liberation Army (TNLA) has seized towns and blocked vital trade routes to Myanmar's northern neighbor.

The offensive has galvanized other opponents of the military, with clashes spreading to Myanmar's western and eastern borders in what analysts say is the biggest military challenge to the junta since it seized power in 2021.

On Friday anti-coup fighters in eastern Kayah state said they had torched a courthouse in the state capital Loikaw amid clashes with security forces in and around the city.

U.N. Secretary-General Antonio Guterres said Wednesday he was "deeply concerned" about the widening conflict.