Gunshots rang out and residents fled burning homes as security forces in western Burma struggled to contain deadly ethnic and religious violence that has displaced thousands of people.
The conflict pitting ethnic Rakhine Buddhists against Rohingya Muslims has left at least a dozen civilians dead and hundreds of homes charred since it began in coastal Rakhine state on Friday.
President Thein Sein has declared a state of emergency and deployed army troops to restore stability, warning that the unrest could threaten the fragile nation's recent democratic reforms as it emerges from half a century of military rule.
In the regional capital, Sittwe, police fired live rounds into the air to disperse a group of Rohingyas who could be seen burning homes in one neighbourhood. An Associated Press photographer saw hordes of people running to escape.
Police fired skywards again in another area to separate hundreds-strong mobs wielding sticks and stones.
Much of the port city remained calm, however, including the main street. Schools, banks and most shops were closed, though some opened briefly to sell fish and vegetables early in the morning to residents who braved the tense streets.
"Tensions are still very high and it is very dangerous," said Tha Zan Hla, an ethnic Rakhine.
The unrest was triggered by the rape and murder last month of a Buddhist girl, allegedly by three Muslims, and the June 3 lynching of 10 Muslims in apparent retaliation. There are long-standing tensions between the two groups.
The government regards the Rohingyas as illegal migrants from Bangladesh and has rendered them stateless by denying them citizenship. Although some are recent settlers, many have lived in Burma for generations and rights groups say they suffer severe discrimination.
The conflict poses one of the biggest tests yet for Burma's new government as it tries to reform the nation after the long-ruling army junta ceded power last year.