At least 34 people were killed in a series of suicide bomb attacks in northeast Nigeria overnight, as the military on Friday warned that Boko Haram threatened the country's sovereignty.
Thirty people died in a double bombing on a mosque in Mulai on Thursday night, Mohammed Kanar, from the National Emergency Management Agency (NEMA) said. In a separate attack, three female bombers blew themselves up and killed four others in nearby Umarari early Friday, he added.
Locals, however, said the death toll was higher from both incidents and that more than 60 may have been killed in total.
No one has claimed responsibility for the attacks but they bore the hallmarks of Boko Haram, which has been trying to carve out a state in the northeast of Africa's most populous country since 2009. Boko Haram also has a track record of attacking mosques, considering places of worship that do not share its radical interpretation of Islam as a legitimate target.
In Mulai, NEMA's Kanar and witnesses said the bombers appeared to have slipped into the mosque disguised as worshippers before evening prayers.
"When rescuers and sympathizers gathered in front of the place, the second one went off, killing many of them," said Amadu Marte, a civilian vigilante assisting the army.
Marte said he and colleagues counted 42 bodies at the scene. Friday's attack in Umarari, a village of mainly poor farmers and laborers some 4.5 miles west of Maiduguri, also happened at a mosque in the early morning.
Witness Dawud Baana said worshippers were preparing for morning prayers at the time. Street vendor Saratu Garba said she heard the blast as she was carrying firewood out of her house and that 19 were killed.
Both areas hit by the most recent attacks are on the outskirts of the Borno state capital of Maiduguri, which has been increasingly targeted by coordinated bomb and suicide attacks in recent weeks. The attacks came just days after Nigeria's President Muhammadu Buhari said he was "fully confident" of ending Boko Haram's six-year insurgency by the end of this year.
The military was "well-positioned to meet the December deadline which they have been given," he said in a statement on Wednesday. But with Maiduguri having been attacked four times this month alone, fresh questions will be asked about security in the city, where Boko Haram, which is allied to the Islamic State of Iraq in the Levant (ISIL), was founded in 2002.
One area of the city, Ajilari Cross, has been hit three times in a month, killing more than 120. There have also been suicide attacks near the capital, Abuja. Overall, some 1,350 people have been killed since Buhari came to power at the end of May, according to a tally by Agence-France Presse.
Earlier this week, Buhari met the head of the U.S. Africa Command, General David Rodriguez, as Washington announced the deployment of up to 300 military personnel to northern Cameroon.
The U.S. military will provide intelligence, surveillance and reconnaissance expertise, the White House said, after similar multiple suicide attacks in Cameroon, Chad and Niger.
Guerrilla-style tactics against "soft" civilian targets such as mosques, markets and bus stations have increased. Last week, 41 people were killed in triple explosions in Baga Sola, on the Chadian side of Lake Chad, where Nigeria meets Niger, Chad and Cameroon.
On Friday, Nigeria's most senior army officer, Chief of Army Staff Lieutenant General Tukur Buratai, told troops "the next few days will be crucial" in the counter-insurgency.
"It is also crucial to our country, Nigeria. Our sovereignty as a nation is threatened. The Nigerian Army and indeed the military as the symbol of our nationhood is being challenged," he said. "Our ability to stand and defeat the Boko Haram terrorists in the next few weeks will determine the future of our country. We cannot afford to lose the fight."