An indefinite 24-hour curfew has been imposed in the northern Nigerian city of Damaturu, a day after it was attacked by militant group Boko Haram.
The Yobe state governor's office said the move would allow the security forces to finish their operation to drive out the attackers.
On Monday, Boko Haram attacked a police base, a university and a school.
A hospital morgue worker said 33 police officers and six soldiers had been killed in clashes with the militants.
He also said the bodies of 20 Boko Haram fighters had been taken to Damaturu hospital.
Reuters quoted a local security source as saying the insurgents had recovered bodies of other fighters from the streets and taken them away in several pick-up trucks.
Boko Haram, which has seized a number of towns and villages in north-east Nigeria, is fighting to create an Islamic state.
It has killed thousands of people and caused many others to flee their homes.
In Maiduguri city, in neighbouring Borno state, on Monday militants detonated two blasts in a market, killing at least six people, according to local medical sources.
Suicide attacks by two female bombers at the same market on 25 November killed 78 people.
A statement issued by an adviser to the Yobe state governor said the decision to impose a curfew on Tuesday had been "taken... as part of measures to enable the security agents, who did a great job yesterday, repelling insurgent attacks on the town, to conclude their ongoing assignment".
BBC Nigeria analyst Naziru Mikailu says the curfew means that all residents will have to stay at home, forcing the closure of schools, businesses and government offices.
It suggests the militants have heavily infiltrated the state capital, which has a population of several hundred thousand, and the authorities are extremely concerned about the security situation, he adds.
Boko Haram has repeatedly targeted Yobe and Borno and a third state, Adamawa, all in north-east Nigeria.
Who are Boko Haram?
- Founded in 2002
- Initially focused on opposing Western education - Boko Haram means "Western education is forbidden" in the Hausa language
- Launched military operations in 2009 to create Islamic state
- Thousands killed, mostly in north-eastern Nigeria - also attacked police and UN headquarters in capital, Abuja
- Some three million people affected
- Declared terrorist group by US in 2013
Residents in Damaturu spoke on Monday of fleeing the city, as militants set off explosions and attacked a police base and a university.
One unidentified government official described the scene to AFP news agency as being "chaos all over the town".
The authorities have struggled to defeat the militant Islamist group, which has been waging an insurgency since 2009.
New York-based Human Rights Watch says Boko Haram has killed more than 2,000 civilians this year.
Damaturu has been targeted by Boko Haram a number of times before. At least 63 people were killed in an attack on churches and police in 2011 in what was then the deadliest attack of the insurgency.
On several other occasions since then, militants and the security forces have engaged in gun battles in the city.
Earlier this year, a suicide bomber in Damaturu targeted a crowd watching a televised World Cup football match, killing more than 20 people.