Terrified women and children hid in forests and police patrolled tense villages in western Myanmar Wednesday, residents said, following sectarian clashes which left five Muslims dead and prompted international alarm.

A day after riots shook the area, President Thein Sein arrived in the town of Thandwe as part of his first visit to Rakhine state since a wave of religious violence erupted there last year.

Around 800 Buddhist rioters swept through one village on Tuesday burning homes and attacking Muslims, according to authorities.

"We are living in fear. Many people, including women and children, are hiding in the forest nearby," local Muslim official Myint Aung told AFP.

"We are disappointed that we have a government that is unable to provide security for us," he said, adding that the police had fired warning shots but could not control the mob.

Five Muslims were killed, a local police official said, including a 94-year-old woman who was stabbed to death.

Four Buddhists were injured in the fighting and a fifth was missing, while 59 houses and a mosque have been torched since tensions flared on Saturday, police said.

A large security presence was seen in the area on Wednesday. Locals picked through the charred rubble of a burnt-out mosque in one village, according to AFP reporters.

The international community has expressed growing disquiet at the fresh unrest in the strife-racked region, where tens of thousands of people remain displaced from earlier clashes that have left Buddhists and Muslims increasingly alienated from one another.

The United States said it was "deeply concerned" about the latest unrest and urged authorities to respond "decisively", in a statement issued by its embassy in Yangon.

United Nations Secretary General Ban Ki-Moon called for "urgent action by the government to protect the vulnerable population" in a meeting with Myanmar's foreign minister on Tuesday, the UN said.

Around 250 people have been killed and more than 140,000 left homeless in several outbreaks of Buddhist-Muslim violence around the country since June 2012, mostly in Rakhine.

Attacks on minority Muslims have overshadowed political reforms in Myanmar as it emerges from military rule, piling pressure on Thein Sein, a former junta general who took power in 2011.

The Myanmar leader is expected to meet community leaders in Thandwe on Thursday after staying in the area overnight.

The region is home to the popular tourist destination of Ngapali Beach although no foreigners were believed to have been caught up in the unrest.

Thein Sein spent Tuesday visiting a different area of Rakhine populated mainly by stateless Rohingya Muslims.

In a message to a multi-faith conference carried in state media on Wednesday, he lamented "instigations" that turned "minor crimes into conflicts between the two communities and two religions".

Four major Myanmar Muslim organisations released an open letter to Thein Sein late Tuesday calling on the government to take urgent law-enforcement action.

"The concerns of minority Muslims around the country have reached peak levels. They feel they have no security," the letter said.

Two outbreaks of unrest in Rakhine last year left about 200 people dead, mostly Rohingya who are denied citizenship by Myanmar and viewed by the government and many local people as illegal immigrants from neighbouring Bangladesh.

The latest clashes follow an argument over a parking space near a Muslim home last week.

Rights groups have in the past accused Myanmar security forces of complicity in the violence -- an allegation denied by the authorities.

Thousands of Rohingya boat people -- including women and children -- have fled the former junta-ruled country since last year, mostly heading for Malaysia on a perilous sea voyage.