Soldiers were out in force Saturday in cities around Bangladesh after another day of lethal clashes between student protesters and police prompted Prime Minister Sheikh Hasina to cancel foreign visits.
This week's violence has killed at least 105 people so far, according to an AFP count of victims reported by hospitals, and poses a significant challenge to Hasina's autocratic government after 15 years in office.
A government curfew went into effect at midnight and the premier's office asked the military to deploy troops after police again failed to subdue mayhem.
"The government has decided to impose a curfew and deploy the military in aid of the civilian authorities," Hasina's press secretary Nayeemul Islam Khan told AFP.
Streets of the capital Dhaka were almost deserted at daybreak, with troops on foot and in armoured personnel carriers patrolling the sprawling megacity of 20 million.
Several rickshaw drivers downtown who ignored the curfew were told by police to return home.
The curfew will remain in effect until 10:00 am (0400 GMT) Sunday, private broadcaster Channel 24 reported.
Hasina had been due to leave the country on Sunday for a planned diplomatic tour but abandoned her plans after a week of escalating violence.
"She has cancelled her Spain and Brazil tours due to the prevailing situation, her press secretary Nayeemul Islam Khan told AFP.
Near-daily marches this month have called for an end to a quota system that reserves more than half of civil service posts for specific groups, including children of veterans from the country's 1971 liberation war against Pakistan.
Critics say the scheme benefits children of pro-government groups that back Hasina, 76, who has ruled the country since 2009 and won her fourth consecutive election in January after a vote without genuine opposition.
Hasina's government is accused by rights groups of misusing state institutions to entrench its hold on power and stamp out dissent, including by the extrajudicial killing of opposition activists.
Police fire was the cause of more than half of the deaths reported so far this week, based on descriptions given to AFP by hospital staff.
"The rising death toll is a shocking indictment of the absolute intolerance shown by the Bangladeshi authorities to protest and dissent," Babu Ram Pant of Amnesty International said in a statement.
Authorities imposed a nationwide internet shutdown on Thursday which remains in effect, severely hampering communication in and out of Bangladesh.
