Suspected Islamist militants have killed dozens of people who were praying at a mosque. Separately, in a new video, the group’s leader threw down the gauntlet to foreign powers, including France, Israel and the US.
The militants were dressed in army fatigues when they gunned down 44 people in Borno state, according to government and civilian sources on Monday.
"Gunmen believed to be Boko Haram members entered the mosque and opened fire on Muslim worshippers, killing 44," a government official said on condition of anonymity, according to the news agency AFP.
The killings were reported to have taken place in Konduga town, 35 kilometers (22 miles) outside the state capital, Maiduguri, on Sunday.
Usman Musa, a member of the Civilian Joint Task Force, which works alongside the military in the fight against Boko Haram, said members of his group had counted the bodies at the mosque after the attack had been carried out.
He told the AP news agency that four of his side's fighters had been killed upon reaching Konduga, where they had faced "heavy resistance from heavily armed terrorists."
Musa said his colleagues had also counted the bodies of 12 dead civilians in the village of Ngom, just 5 kilometers outside Maiduguri.
A state of emergency was declared in much of the northeast of the country in May as the government launched a crackdown on the insurgents. Members of Boko Haram have said they aim to impose Shariah law across the country of some 160 million, divided almost equally between a Muslim north and a Christian south.
Although it was unclear why the insurgents would have targeted the mosque, Boko Haram has in the past attacked mosques where clerics have condemned religious extremism. The attack was also linked with an effort to punish locals over the formation of civilian vigilante groups.
News of the attack filtered out after journalists received a video in which Boko Haram boasted about recent attacks and promised that more would be carried out.
'No match for me'
The video, received by journalists on Monday, shows leader Abubakar Shekau refute speculation that he might have been killed. "You have not killed Shekau," he said, saying that Boko Haram was responsible for several deadly attacks in recent months.
Shekau - who is said to lead the group's most radical faction - boasted that his insurgents were stronger than the Nigerian military and that they were now strong enough to confront the US.
"I'm challenging Obama," Shekau said, issuing similar offers to French President Francois Hollande and Israeli Prime Minister Benjamin Netanyahu. "They are no match for me."
Shekau has been declared a global terrorist by Washington, which has placed a $7 million (5.3-million-euro) bounty on his head.
The insurgency is estimated to have claimed more than 3,600 lives since 2009, including killings by the security forces.
rc/jm (AFP, AP, Reuters)