Boko Haram Islamic extremists struck a city and a town in northeastern Nigeria with rocket-propelled grenades and multiple suicide bombers Monday, killing at least 80 people, witnesses said.

In Maiduguri, the capital of Borno state, at least 30 were killed and more than 90 wounded in overnight blasts and shootouts, and another 20 died in a bombing outside a mosque at dawn Monday, said Muhammed Kanar, area coordinator of the National Emergency Management Agency.

A twin suicide bombing also killed at least 30 people in Madagali, a town 150 kilometers (95 miles) southeast of Maiduguri, witnesses said. Danladi Buba said two women blew themselves up at a market near a busy bus station at about 9 a.m. Brig. Gen. Victor Ezugwu, the officer commanding in northeast Adamawa State, confirmed the attack but said casualties have yet to be established.

The attacks appear to be a challenge to President Muhammadu Buhari's declaration last week that Nigerian security forces have "technically won the war" against Boko Haram and that it is now capable of no more than suicide bombings on soft targets.

Maiduguri, with a population of about 1 million people, now hosts almost as many refugees — among the 2.5 million people driven from their homes in the 6-year-old Islamic uprising. About 20,000 people have been killed in Nigeria and hundreds others elsewhere as the insurgents have carried their conflict across its borders into Cameroon, Niger and Chad.

The military said there had been multiple attacks at four southwestern entry points to Maiduguri.

In another blast, two girls blew themselves up in the Buraburin neighborhood, killing several people, according to civil servant Yunusa Abdullahi.

"We are under siege," Abdullahi said. "We don't know how many of these bombs or these female suicide bombers were sneaked into Maiduguri last night." He said some residents have found undetonated bombs.

Maiduguri is the birthplace of Boko Haram, which emerged as a much more radical entity after Nigerian security forces launched an all-out assault on their compound in the city, killing 700 people in 2009.

Acting on information provided by a captured insurgent, Nigerian troops "intercepted and destroyed" 13 suicide bombers and arrested one female suicide bomber in repelling the attackers, Maj. Gen. Lamidi Adeosun, the commander prosecuting Nigeria's war against Boko Haram, told reporters.

Defense Ministry spokesman Brig. Gen. Rabe Abubakar tweeted that "Boko Haram Terrorists On suicide bombing #mission during the Festive period were nabbed in #Kaduna & other areas." Soldiers arrested seven Boko Haram bomb specialists in the northern city on Sunday, according to PR Nigeria, which issues government statements.

Just outside Maiduguri, militants firing indiscriminately from the back of three trucks attacked the outlying village of Dawari, soldiers engaged them, and as people were fleeing, a woman ran into the area yelling "Boko Haram, Boko Haram." When people gathered, she detonated herself, according to village head Bulama Isa.

A rocket-propelled grenade then exploded, setting alight grass-thatched huts, and a second woman blew herself up, according to Isa. Among those killed was the village chief and 10 of his children, according to residents Ahmed Bala and Umar Ibrahim.

A soldier said the insurgents fired rocket-propelled grenades into four residential areas on the outskirts of the city. Soldiers fired back, and many civilians were caught in the crossfire, according to the soldier, who spoke on condition of anonymity because he is not authorized to speak to journalists.

Three suicide bombers blew themselves up at a home near Bakassi Estate, killing 18 people Sunday evening, another soldier told The Associated Press.

A nurse at Maiduguri Specialist Hospital said dozens of critically wounded, mainly children and women, may not survive. A doctor at the hospital later said four of the wounded have died and the number of injured has risen to about 100. Like the nurse, he spoke on condition of anonymity because he is not authorized to speak to reporters.

The nurse said the hospital was so overflowing with patients that some had to be cared for in the maternity ward. About 60 people had wounds from bullets and shrapnel from explosive devices, she said. Other wounded people had to be sent to other hospitals in the city.

Among them was a baby found dead, still tied to the back of her mother, who survived after being hit by shrapnel, the nurse said.

It was hard to do a body count because so many had been blown into pieces, she said, describing torsos and dismembered arms and legs.