The mobs destroyed mosques and burned dozens of homes over the weekend despite attempts by the government to stem the nation's latest outbreak of sectarian violence.
In an announcement Monday night on state television, the government pledged to make "utmost efforts" to halt the violence and incitement of racial and religious unrest.
"We also urge the people to avoid religious extremes and violence which could jeopardize the country's democratic reform and development," it said.
President Thein Sein had declared an emergency in the affected areas of central Myanmar on Friday and deployed army troops to the worst-hit city, Meikhtila, where at least 32 people were killed. According to the U.N., more than 12,000 people were displaced. Monday's announcement said the displaced people would be resettled as soon as calm was restored.
Muslims in Meikhtila, who make up about 30 percent of the city's 100,000 inhabitants, appeared to have borne the brunt of the devastation. At least five mosques were set ablaze from Wednesday to Friday, and most homes and shops burned were Muslim-owned.
The authorities said they detained at least 35 people allegedly involved in arson and violence.
The upsurge in sectarian unrest casts a shadow over Thein Sein's administration as it struggles to make democratic changes after half a century of army rule officially ended two years ago this month.
Similar violence that rocked western Rakhine state last year, pitting ethnic Rakhine Buddhists against Rohingya Muslims, killed hundreds and drove 100,000 from their homes.
The emergence of sectarian conflict beyond Rakhine state was an ominous development, one that indicates anti-Muslim sentiment has intensified nationwide since last year and, if left unchecked, could spread.
Muslims account for about 4 percent of the nation's roughly 60 million people, and during the long era of authoritarian rule, military governments twice drove out hundreds of thousands of Rohingya, while smaller clashes occurred elsewhere. About one third of the nation's population consists of ethnic minority groups, and most have waged wars against the government for autonomy.
The latest bloodshed "shows that inter-communal tensions in Myanmar are not just limited to the Rakhine and Rohingya in northern Rakhine state," said Jim Della-Giacoma of the International Crisis Group. "Myanmar is a country with dozens of localized fault lines and grievances that were papered over during the authoritarian years that we are just beginning to see and understand. It is a paradox of transitions that greater freedom does allow these local conflicts to resurface."
Local authorities in the nation's largest city, Yangon, more than 500 kilometers (300 miles) south of Meikhtila, told shop owners to close by 8:30 p.m. or 9 p.m. Monday night. A police officer contacted by phone from the city's Sanchuang township described the action as a precautionary measure. He declined to give his name.
Earlier Monday, Deputy Information Minister Ye Htut warned that instigators of violence were stoking rumors to heighten people's anxieties and emotions.
For most of Monday, false rumors circulated that riots had broken out in parts of Yangon, and that people were planning to burn down mosques and a busy market called Yuzana Plaza, where many shopkeepers hurriedly shut their stalls. Police were dispatched to Mingalartaungnyunt, an eastern suburb, to secure the area, although no violence occurred.
Ye Htut on his Facebook page warned people not to believe in rumors and to inform the authorities of any suspicious activity.