Myanmar camp
Thandawli villagers stand by the bank of a river in a Rohingya internally displaced persons (IDP) camp outside of Sittwe on May 14, 2013 REUTERS

A boat carrying more than 100 Rohingya Muslims, who were fleeing a cyclone that threatened to strike flood-prone Rakhine state, capsized off western Myanmar, the U.N. said on Tuesday.

The boat sank off Pauktaw township in Rakhine state late on Monday, leaving an unknown number of people missing, the BBC reported.

About 140,000 people displaced by communal violence last year have been living in makeshift camps across Rakhine raising concerns that they're vulnerable to cyclone Mahasen, which is expected to cross between Northern Rakhine and neighboring Bangladesh coasts on Thursday evening.

The U.N. had called for an urgent evacuation ahead of the storm, warning that many areas where displaced people are now living are in low-lying coastal areas at risk of flooding or tidal surges.

Myanmar's Department of Meteorology and Hydrology said at 1 p.m. local time on Tuesday that the storm is moving northward with maximum wind speed estimated at 60 mph near the cyclone's center.

The approaching storm hasn't yet reached Myanmar's coasts, the advisory added. Trawlers, vessels and ships were advised to avoid the area.

Local officials told Agence France-Presse that Myanmar’s army had been deployed in preparation for the cyclone to help relocate thousands of displaced people living in low-lying coastal areas.

Barbara Manzi, head of the U.N. Office for the Coordination of Humanitarian Affairs, told the BBC from Sittwe that search and rescue operations continue for the missing boat people.