Suspected Boko Haram militants have struck in two state capitals in north-east Nigeria, with suicide attacks by female bombers in Maiduguri and a raid on a police base in Damaturu.
At least 10 people were killed in the twin blasts at a crowded market in Maiduguri, police said.
In Damaturu, explosions and gunfire were heard as militants rampaged through the city, residents said.
Boko Haram has vowed to create an Islamic state in areas it controls.
The blasts at Monday market in Maiduguri, the state capital of Borno, were caused by 'two girls', witness Mallam Muhammadu told Associated Press (AP) news agency.
At least 32 people wounded in the explosions at Monday market, a source at the local hospital told the BBC Hausa service.
Confirming the attacks, police spokesman Gideon Jibrin told the AFP news agency: 'Two female suicide bombers detonated an explosive in Monday market in two different locations killing more than 10, and injured many.'
Suicide attacks by two female bombers at the same market on 25 November killed 78 people.
Maiduguri was the headquarters of Boko Haram, until it was driven out of the city earlier this year by the security forces and vigilante groups.
'Chaos all over town'
'Start Quote
We have left our homes. We are now in the bush'
End Quote Umar Sada Damaturu resident
The assault on Damaturu, the capital of neighbouring Yobe state, began shortly after 05:00 local time (04:00 GMT), forcing most residents to stay indoors or to flee the city.
The militants set fire to a riot police base, and attacked a primary school and the city's university.
A university student told BBC Focus on Africa he had been woken by the sound of explosions and had seen a large number of militants wearing military uniforms moving into the city.
He said he and some other residents had since fled to the surrounding countryside.
Another resident told the BBC that schools and businesses were shut, and most people were staying at home.
Boko Haram militants had stormed an empty primary school, and were firing shots from there, he said.
'We have left our homes. We are now in the bush. We don't know what's going to happen,' resident Umar Sada told AFP.
A government official, who asked not to be identified, said: 'It's chaos all over the town. All I can hear is explosions and gunfire from my house.
'I couldn't go out for morning prayers because this started before dawn and I'm afraid to leave in case I get caught up in it.'
Boko Haram has taken control of a series of towns and villages in north-east Nigeria in recent months.
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 Escape from Boko Haram Who are Boko Haram? Profile: Boko Haram leader Abubakar Shekau
The authorities have struggled to defeat the militant 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.
On Friday, more than 100 people were killed in a gun and bomb attack on a mosque in the city of Kano.
The identity of the attackers has not been confirmed but Boko Haram has been widely blamed.
Damaturu has been targeted by Boko Haram a number of times before.
Entities 0 Name: Boko Haram Count: 12 1 Name: Maiduguri Count: 4 2 Name: Nigeria Count: 3 3 Name: Damaturu Count: 2 4 Name: Umar Sada Count: 1 5 Name: Abuja Count: 1 6 Name: Associated Press Count: 1 7 Name: bush Count: 1 8 Name: Abubakar Shekau Count: 1 9 Name: Umar Sada Damaturu Count: 1 10 Name: Gideon Jibrin Count: 1 11 Name: Boko Haram Who Count: 1 12 Name: BBC Hausa Count: 1 13 Name: Yobe Count: 1 14 Name: BBC Count: 1 15 Name: AP Count: 1 16 Name: Human Rights Watch Count: 1 17 Name: AFP Count: 1 18 Name: Hausa Count: 1 19 Name: Kano Count: 1 20 Name: US Count: 1 21 Name: Mallam Muhammadu Count: 1 22 Name: UN Count: 1 23 Name: Borno Count: 1 24 Name: BBC Focus on Africa Count: 1 Related 0 Url: http://ift.tt/1y83q5B Title: Nigeria gunmen 'raid Damaturu city' Description: Suspected Boko Haram militants have carried out attacks on the city of Damaturu in north-east Nigeria, residents and security sources say. The assault on the city, the capital of Yobe state, began shortly after 05:00 local time. Gunshots and explosions were heard and a base of the riot police was reported to have been set on fire.
