At least 30 people have been killed and dozens have been injured in twin suicide bomb attacks on a mosque in the Mulai area of Nigeria's northeastern Borno State, health officials tell Al Jazeera.

Sources said the force of the blast destroyed the mosque as worshippers were praying.

On Location: Fighting Boko Haram in Borno State

One bomb exploded inside the mosque, while another exploded outside, sources said.

"Suicide bombers targeted large crowds to cause maximum damage," Al Jazeera's Ahmed Idris, reporting from Maiduguri, said.

There was no immediate claim of responsibility for the attack, but among the suspects will be the Boko Haram armed group, which has launched a large number of suicide attacks in the region over the past few months.

On Wednesday, three blasts in Borno's capital Maiduguri killed at least five civilians and three suspected suicide bombers after the attackers were challenged by locals.

On October 1, at least 10 people were killed and 39 injured when four suicide bombers blew themselves up in a wave of attacks in Ajilari Cross, which is near Maiduguri airport and a military base.

On September 20, at least 117 were killed in the city when attackers hit a mosque and killed football fans watching a televised match, as well as bystanders.

Al Jazeera's Idris said that the Nigerian army has had some success in pushing Boko Haram from territory it had claimed in its bid to carve out an Islamic state in the country's northeast.

But he said that security forces have been unable to prevent the group from carrying out suicide bomb attacks, which have increased in frequency.

 

Source: Al Jazeera and agencies