Fighting between Myanmar's military and ethnic Rakhine rebels in Mrauk U, the ancient capital of the Rakhine kingdom, has left at least eight locals injured, scaring tourists and sparking fears that the historical monuments are under threat.

Now the military is waging war against the Arakan Army (AA), which claims to represent ethnic Rakhine Buddhists and has killed 22 officers since early January.

Over the weekend the conflict spread to Mrauk U, renowned for its ancient temples and popular with hardier travellers.

He also confirmed the deaths of two men from a nearby village, who were wounded last week from the fighting.

A British tourist posted videos on Twitter of him and his fiancee exploring the temples on Sunday, clearly worried by the sound of gunfire and explosions outside.

Christopher Caddy told AFP they thought it was just military training -- until they came out of one temple and realised the vendors and security had fled.

It suddenly felt "more real", he said, adding that a local arrived on a moped to pick up friends and he told them to get out as well.

As they cycled back to their hotel, they could see soldiers in "combat positions behind the ruins" of a neighbouring pagoda.

Hotels contacted by AFP had no guests left.

One staff member, requesting anonymity, said his hotel had been hit in the crossfire on Sunday night.

"The windows of our hotel were destroyed in the shooting," he said.

Local historian Khin Than told AFP she did not dare to go assess the damage done to the monuments yet.

"There are still armed groups deployed in the hills nearby," she said by phone. "We are still scared."

Myanmar hopes to obtain UNESCO world heritage status for Mrauk U, and the Myanmar Archaeology Association Monday expressed concerns that the ongoing clashes might affect its nomination.

It issued an emergency appeal for all sides to demarcate the town as a "fire-free zone".

The army said they deployed troops to downtown Mrauk U after receiving a tip-off the AA was going to mount an attack.

The insurgent group could not be reached for comment.

Authorities have vowed to crush the rebellion, which has simmered since the group's formation in 2009.

The rebels enjoy widespread support from ethnic Rakhine, who have felt marginalised for decades in one of the country's poorest states.

But thousands have been displaced by the spreading violence which is also edging closer to the state capital Sittwe.

Much of Rakhine is in a strict lockdown and information is difficult to verify independently.