KANO, Nigeria (AP) -- An explosion at a medical school in Nigeria's northern city of Kano killed at least eight people and wounded 12, according to police who blamed Islamic extremists.
Kano state police Commissioner Aderenle Shinaba said one suspect was detained and his vehicle seized for investigation.
At the School of Hygiene in a northern residential suburb of Nigeria second largest city, an ambulance rushed out of the cordoned off gate.
"People were shouting 'Get out! It's a bomb!" said student Aishatu Musa. She said she ran along with everyone else.
Shinaba told The Associated Press "There was an explosion in the school this afternoon by 15:05 hours and it happened right inside the school premises." It was the third bomb blast in four months in Nigeria's second largest city.
He said 20 people were taken to the hospital, but eight died.
Boko Haram did not immediately claim responsibility but the school matches two of its targets -- schools and Western medicine. Boko Haram has attracted international condemnation since April when it kidnapped more than 200 schoolgirls who remain captive.
The U.S. Embassy in Nigeria, promoting a new U.S. government effort to support girls' education worldwide, Monday posted on Twitter, "When we #LetGirlsLearn, we improve the stability of a nation."
U.S. drones and experts are among foreigners helping in the search to rescue the girls.
Nigeria's government and military have failed to curb the 5-year-old Islamic uprising despite a year-old state of emergency in three northeastern states -- not including the northern state of Kano -- that cover one-sixth of the country.
This year, the insurgents have embarked on a two-pronged strategy -- bombing in cities and a scorched-earth policy in rural areas where they are devastating villages. The capital, Abuja, the central city of Jos and northeastern state capital of Maiduguri, the birthplace of Boko Haram, all have been bombed.
On Saturday, scores of Boko Haram fighters attacked four villages near Chibok town, from which the girls were kidnapped. Witnesses said Monday that at least 33 villagers were killed as well as six vigilantes from civilian groups that have recently had some success in repelling Boko Haram.
A spokesman for the vigilantes, Muhammed Gava, said his group killed at least 25 insurgents.
Villagers who escaped said the attackers drove into town Saturday morning and just opened fire on anyone in sight. When people tried to escape into the bush, they pursued them on motorbikes and shot them down, said survivors who walked to Chibok. They spoke on condition of anonymity for fear of reprisals.
Scores of huts were set ablaze and burned down, said villager Pogu Shikarkir, who helped bury 25 corpses.
The military did not immediately respond to the attack, with some 200 soldiers and about 100 police officers in Chibok refusing to go to the scene though the nearest village, Kwarangilam, is just 15 kilometers (nine miles) away, residents said.
An Air Force plane responded Saturday afternoon, bombing two armored cars filled with Boko Haram fighters and strafing remaining fighters, said a soldier who spoke on condition of anonymity.
That allowed villagers to return to bury their dead.
In Chibok, citizens are fearful that the insurgents will assault the town again. "We live in fear," explained a man who said he was too old to abandon his home and become a refugee. Hundreds of thousands of people have fled, some to the neighboring countries of Cameroon, Chad and Niger.
Meanwhile the fate of the girls appears to have reached an impasse. Nigeria's military has said it knows where they are but fears their abductors would kill them if any military action is taken. Boko Haram is demanding the release of hundreds of detainees but President Goodluck Jonathan has said he will not consider a prisoner swap.
Politics have bedeviled the issue, with many politicians distracted by upcoming presidential elections in February 2015, with the first lady, Patience Jonathan, claiming the mass abduction was the fabrication of her husband's enemies.
Last week, a presidential committee investigating the kidnappings stressed that it did in fact happen and clarified the number of students who have been kidnapped. It said there were 395 students at the school, 119 escaped during the siege of the school, another 57 escaped in the first couple of days of their abduction, leaving 219 unaccounted for.
Faul reported from Lagos, Nigeria. Associated Press writer Haruna Umar contributed to this report from Maiduguri, Nigeria.
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