Communal riots in Myanmar have spread closer to the main city Yangon, police said Tuesday as the United States warned against travelling to parts of the country in the wake of unrest that has left 40 dead.

Fresh Buddhist-Muslim violence broke out late Monday and again on Tuesday in villages in the Bago region roughly 150 kilometres (90 miles) north of Yangon, with several mosques and dozens of homes reported to have been destroyed.“Police and soldiers had to control the clashes almost the whole night,” a police officer who did not want to be named told AFP, adding that another mosque was destroyed on Tuesday in the town of Oakpho.

In a statement on its website, the US Embassy “strongly advised” citizens to avoid travel to the Mandalay region - where the unrest began - as well as to a Muslim neighbourhood in Yangon near the Mingalar Market/Yuzana Plaza.The clashes are a stark reminder of the challenge that Muslim-Buddhist tensions pose to Myanmar’s government as it tries to reform the country after decades of iron-fisted military rule ended two years ago. Witnesses said the violence appeared to be organised.

Kyaw Thet, a member of the “88 Generation” pro-democracy movement in Sittwin in Bago region, said dozens of strangers on motorcycles arrived late on Monday and destroyed the town’s mosque. “Then they went to a tea shop owned by Muslims and destroyed the inside of the shop,” he said by telephone. “Before they came, we had a blackout in the town and our telephone lines were cut. They also incited people to commit violence,” he added.

A resident in nearby Gyobinggauk said local authorities had announced a nighttime curfew over loudspeakers and soldiers had arrived in the town.The clashes first began on March 20 in Meiktila, 130 kilometres north of the capital Naypyidaw, apparently triggered by an argument in a gold shop that turned into an escalating riot during which mosques were burned, houses razed and charred bodies left lying in the streets. Since then dozens of people have been detained in connection with the violence, which saw armed rioters - including Buddhist monks - roam the streets of Meiktila, threatening visiting journalists.

After a state of emergency was declared on Friday and the army was sent in, an uneasy calm has returned to Meiktila, where a nighttime curfew has been imposed.The violence has however raised nervousness elsewhere in the ethnically diverse country, including in Yangon where police have been instructed to be extra vigilant, a second police officer told AFP. “

Police in every township are on alert and ready in case something happens,” he said, adding that some soldiers had also been on patrol in the former capital. Restaurants or shops selling alcohol in Yangon were on Monday ordered to close by 9:00 pm in a move aimed at stopping the spread of rumours, police said.