|A bomb attack carried out by Boko Haram suspects killed 185 people in the Nigerian city of Kano in January [reuters]
A series of explosions and gunfire has echoed through the northeast Nigerian town of Gombe.
Reports said the blasts happened around the time of evening prayers, quickly followed by gunfire.
"It started around 1830 GMT and it kept on going off," said Jimam Lar, a Phd researcher doing field work in Gombe
who heard the blasts from his hotel room.
"I've heard several bombs. It's a good number. I can't say exactly how many, but it went on for over an hour at intervals,"said Lar to the Reuters news agency.
Witnesses said people were fleeing an area of the city near a prison and police station. It is not clear if there are casualties.
Gombe has previously been targeted by the Islamist sect Boko Haram. In January, an attack on a church in the city left six worshippers dead.
Boko Haram, whose name means "Western education is forbidden" in the local Hausa language, is carrying out increased attacks in its campaign to implement strict Shariah law in Nigeria, a multi-ethnic nation of more than 160 million people.
It has been responsible of a series of deadly attacks and assassinations across northern Nigeria in the past 17 months.
According to an Associated Press count, in 2012 alone, Boko Haram has been blamed for killing at least 310 people.
Gunmen also launched simultaneous gun and bomb attacks on a prison and a police station in Gombe as well.
The attackers staged what residents said appeared to be coordinated attacks on a main prison where some Boko Haram members are believed to be held, and on a nearby police station.
"We are under siege. A large number of gunmen have encircled the prison, shooting and detonating explosives. It is clear they are Boko Haram," a prison warden told the AFP news agency from inside the central prison in Gombe.
Five killed in Kano
In a separate incident on Friday, suspected Boko Haram members shot dead five Muslim worshippers at a mosque in the northern Nigerian city of Kano.
Gunmen on motorcycles entered the mosque in the Tudun Maliki area of the northern city during evening prayers on Friday and opened fire, killing five people, including the head of a state-funded local vigilante group.
"Two gunmen on a motorcycle opened fire on a congregation in a mosque around 1730 GMT and killed five people," said Kano state police spokesperson, Magaji Majid.
He refused to speculate on who was behind the attack.
However, local witnesses blamed Boko Haram, saying the vigilante chief was their chief target.
"It is clear the attack was carried out by Boko Haram, Sule Kwaram (the vigilante head) was their primary target," said witness, Baffa Hayatu.
Local vigilantes have joined the special security unit set up to curb Boko Haram attacks in Kano following the January 20 deadly attacks where 185 people were killed by the Islamist group.