YANGON (Reuters) - Homes burned, gunshots rang out and witnesses reported many dead as sectarian violence raged for a fifth day between Rohingya Muslims and Buddhists in northwest Myanmar on Tuesday, threatening the country's nascent democracy.
Security forces struggled to stem the worst communal violence since Myanmar's reformist government replaced an oppressive junta last year and vowed to forge unity in one of Asia's most ethnically diverse countries.
Hundreds of Rohingyas have been turned away by authorities in neighbouring Bangladesh after attempting to flee the fighting in boats, say officials and witnesses.
The fighting in Sittwe, capital of Myanmar's Rakhine State, has prompting President Thein Sein to declare a state of emergency, impose dawn-to-dusk curfews and warn that "vengeance and anarchy" could jeopardise the country's fledgling transition to democracy after nearly 50 years of army rule.
"Almost all of the shops have closed. We only have a little bit to eat because the market is also closed," said a worker at a hotel in the centre of Sittwe.
Witnesses reported black smoke over Sittwe, a port town riven by tensions between Buddhists and Muslims. Some Buddhists have been seen carrying bamboo stakes, machetes and sling-shots. Muslims and Buddhists were seen setting houses on fire.
The United States and European Union urged calm to prevent a derailing of Myanmar's fragile reforms.
"Violence between each group is still continuing and is getting worse today in Sittwe. One Rakhine man died in the rioting this morning," said Aung Myat Kyaw, a member of the Rakhine state parliament.
He said about 5,000 people had taken refuge in Buddhist monasteries and schools in Sittwe.
Shwe Maung, a Muslim lower house representative in the ruling Union Solidarity and Development Party for the town of Buthidaung, urged the army to intervene and accused police of allowing Buddhists to break the curfew and burn Muslim houses.
"Sittwe is like a war zone," he said, putting the death toll at 50 in the village of Narzi, not far from Sittwe.
Already, the unrest is undermining the image of ethnic unity and stability that helped persuade the United States and Europe to suspend economic sanctions this year.
The violence, which first erupted on Friday in the town of Maungdaw, could also force the government to confront a long-festering question of how to resolve the plight of thousands of stateless Rohingya Muslims on Myanmar's border with Bangladesh.
Many toil in abject poverty, often despised by ethnic Rakhine, members of Myanmar's Buddhist majority.
Medical aid group Medecins Sans Frontieres suspended its operations in the area on Tuesday, a day after the U.N. refugee agency pulled out its staff. More than 4,000 people driven from their homes are in six shelters, Myanmar state media said.
The official death toll remains eight people killed over several days, but witnesses said the number was substantially higher, although that this could not be independently confirmed.
Amid the violence, Bangladeshi paramilitaries, police and coastguard pushed back 12 wooden boats on Monday carrying 300 Rohingyas, mostly women and children, and witnesses said three more with some 150 people on board were drifting in waters close to the border.
Witnesses said they saw just 20 Rohingyas who had made it into Bangladesh, about half of whom were injured, but their whereabouts were not known. A Bangladeshi official on St Martin's island said the remaining boats had tried to reach the shore but were turned back.
"The boats moved around for a couple of days trying to land on this island but eventually were driven out of our water this morning," Mohammed Nurul Amin, head of a district council, told Reuters by telephone.
"Islanders are also keeping an eye out for any further crossing attempts," he said.
Buddhist-majority Myanmar's government regards the estimated 800,000 Muslim Rohingyas in the country as illegal immigrants from Bangladesh and denies them citizenship. Bangladesh has refused to grant Rohingyas refugee status since 1992.
Bangladesh's Foreign Ministry said it supported Myanmar's efforts to restore order and said it was acting in the best interests of both countries by ensuring developments in Myanmar "do not have any trans-boundary spill-over". The countries are separated by a river flowing into the Bay of Bengal.
Rohingya activists have demanded recognition as a Myanmar ethnic group, claiming a centuries-old lineage to Rakhine.
U.S. Secretary of State Hillary Clinton on Monday echoed Thein Sein's warning the unrest threatened to endanger democratic and economic reforms in the former Burma if it spiralled out of control.
"The situation in Rakhine state underscores the critical need for mutual respect among all ethnic and religious groups and for serious efforts to achieve national reconciliation," Clinton said in a statement.
U.S.-based Human Rights Watch called for diplomats and foreign journalists to be given access to the area and criticised Thein Sein for handing power to security forces. It said troops had opened fire on Rohingyas in Rakhine State, also known by its former name Arakan.
"Deadly violence in Arakan State is spiralling out of control under the government's watch," the group's deputy Asia director, Elaine Pearson, said in a statement.
What sparked the rioting is not known, but it came as tension between Buddhists and Muslims simmered in the wake of reports of a gang rape and murder of a Buddhist woman, widely blamed on Muslims.
That led to the killing of 10 Muslims on June 3, when a Buddhist mob stopped a bus they were travelling on. The dead bus passengers had no connection to the murdered woman; state media says three Muslims are on trial for the woman's death.
Curfews are in place in three Myanmar towns, including Thandwe, the gateway to tourist beaches, and Kyaukphyu, where China is building a port complex.
Chinese Foreign Ministry spokesman Liu Weimin urged Chinese citizens and companies to boost safety precautions and said China "supports Myanmar's efforts in maintaining stability and ethnic harmony".
Additional reporting by; Nurul Islam in Cox's Bazar, Andrew R.C. Marshall in Bangkok, Sui-Lee Wee in Beijing; Writing by Martin Petty and Jason Szep; Editing by Alan Raybould and Ed Lane