The military-backed government imposed an indefinite curfew on six cities across Bangladesh, including the capital Dhaka, from Wednesday night after a string of violent demonstrations.
"The government has declared a curfew in six divisional cities from 8:00 pm (1400 GMT) until further notice," said Fahim Munaim, press secretary to the head of the emergency government.
All colleges and universities in the six cities would also be closed.
Students in the six cities should also leave their halls of residence, Munaim added, without elaborating.
The announcement followed a third straight day of sporadic violence in the capital. Protesters and police have also clashed in northwestern Rajshahi and southeastern Chittagong.
The six cities affected were Dhaka, Rajshahi, Chittagong, northeastern Sylhet, and southern Barisal and Khulna, Munaim said.
The demonstrations took place in defiance of an emergency ban on protests. They began after students at Dhaka university alleged they were man-handled by army personnel and demanded that the army withdraw from the campus.
The interim government took power on January 12 after months of violence over vote-rigging allegations.
On January 11, a state of emergency was declared, polls scheduled for the same month were cancelled and party political activity suspended.
The government has pledged to hold polls by late 2008 after carrying out wide-ranging reforms to clean up Bangladesh's notoriously graft-ridden politics.
The government has enjoyed broad popular support after nearly two decades of misrule by corrupt politicians, although there has recently been rumbling discontent among the very poor about the rising prices of essential goods.
However, the very poor did not appear to be involved in the demonstrations. The government has accused criminals without any genuine grievance of hijacking the student protests.
