Myanmar President Thein Sein's Declaration of Arrakan Emergency in Myanmar.

BANGKOK — Myanmar on Sunday declared a state of emergency in a western state where at least 17 people have been killed this month in sectarian violence between Buddhists and Muslims.

The violence poses another obstacle to the government of President Thein Sein as he tries to open up the country after years of isolation imposed by a military junta and steer it toward democracy.

Soldiers and police officers are trying to restore order in villages where clashes between Buddhists and Muslims have left many villagers wounded and 500 homes burned on Friday and Saturday alone. Four people were wounded in clashes on Sunday, The Associated Press reported.

President Thein Sein's Original Declaration of Arrakan Emergency in Myanmar.

Mr. Thein Sein, a former general, announced the state of emergency on national television on Sunday evening. It was unclear what the practical consequences of emergency rule would be; the military and the police in Myanmar, formerly known as Burma, already wield significant power despite the country’s move toward democracy.

Mr. Thein Sein has made national reconciliation between the Burmese majority and the country’s vast patchwork of ethnic group a priority of his presidency.

Thein Sein Addressing the Nation on the Arrakan Emergency.

But the tensions near the border with Bangladesh fall outside the scope of reconciliation efforts because they involve people from a Muslim ethnic group, the Rohingya, whose members the government does not recognize as citizens.

Tensions in the area had been building for several months, according to Chris Lewa, an expert on the Rohingya who has championed their cause.

Myanmar’s government has not proposed a solution for the 800,000 Rohingya, who live in conditions that resemble refugee camps and make up one of the largest groups of stateless people in Asia.

There are fears inside Myanmar that the clashes could widen into a broader religious conflict. In recent days, Buddhist and Muslim groups have held relatively small separate protests in Myanmar’s main city, Yangon.

Troops Facing the Bengali Muslim Rioters in Maungdaw.

In one sign that passions are running high, the Web site of Eleven Media Group, publisher of one of the country’s leading weekly newspapers, displayed a string of hateful comments about Muslims from readers.

“Terrorist is terrorist,” wrote one reader who signed in as Maungpho. “Just kill them.”

U Ko Ko Gyi, a former political prisoner who is helping lead efforts to ease religious tensions, said he was concerned by the “emotional response” to the clashes. “We have to calm down and find an intellectual solution to the problem,” he said.

Muslims leaders have urged calm in recent days, and the National League for Democracy, the party of the Nobel laureate Daw Aung San Suu Kyi, issued a statement on Saturday calling on the government to restore order. About 90 percent of Myanmar’s population is Buddhist; Muslims account for about 4 percent.

For now the government appears to be confident that the clashes can be contained.

“It’s not likely that this will spread,” said U Tin Maung Thann, the president of a research organization in Yangon who is helping lead the government’s peace talks with other ethnic groups. “The Muslim community within Burma proper have long experience living with the Buddhist majority.”

In recent weeks Mr. Thein Sein’s government has faced protests in several cities over electricity cutoffs and strikes at factories outside Yangon. The government’s tolerance for these demonstrations has reinforced the idea that the country is moving away from years of military dictatorship, but the protests also underscore the long list of challenges and demands facing Mr. Thein Sein as he tries to carry out his reform program.

The violence in Rakhine State was set off by the rape and murder of a Buddhist last month, according to Ms. Lewa, which prompted a series of “revenge attacks.” On June 3, 10 Muslim men were reportedly dragged from a bus and killed. On Friday, mobs of Muslim men attacked Buddhist villagers, leaving seven people dead, according to Burmese media.

Photographs over the weekend showed villagers in the affected area carrying swords and sharpened bamboo poles.

In this generally impoverished country, the Rohingya, many of whom who have been in Myanmar for several generations, are perhaps the most vulnerable minority, plagued by what one United Nations official has called a “chronic crisis.”

They are not allowed to own land, they suffer frequent food shortages and they are technically restricted from travel outside of Rakhine, which borders Bangladesh. Thousands have fled the country by boat in recent years seeking work in Malaysia and other neighboring countries. There are also hundreds of thousands of Rohingya on the Bangladeshi side of the border.

The Rohingya issue stirs a strong nationalist response even among the most liberal members of Burmese society. Mr. Ko Ko Gyi, who spent 18 years in prison for opposing the previous military government, said that the Rohingya were not one of the country’s accepted nationalities and that the “international community” must find a solution to the problem of their statelessness.

“This a question of national sovereignty,” he said. “Anybody who wants Myanmar citizenship will have to learn one of Myanmar’s national languages and learn about our culture.”

Yakhine (Arrakan) State Map in Burmese.

A survey carried out on the Myanmar side of the border by the United Nations in June 2008 found that more than half of Rohingya were illiterate.

There is no hard-and-fast definition of what constitutes the Rohingya, whose skin is typically darker than the Burmese. Muslims living in the northernmost reaches of Rakhine State are generally called Rohingya regardless of their ancestry. Government officials often refer to them as Bengalis.