Twin bombs killed at least 40 people at a market in the central Nigerian city of Jos on Thursday, just eight weeks before Africa's most populous nation holds elections, Reuters reported. Meanwhile, a 13-year-old girl was arrested in another Nigerian city for allegedly wearing a suicide vest, according to Agence France-Presse.

The Sunni Islamic militant group Boko Haram, which rose to infamy worldwide after it kidnapped nearly 300 schoolgirls earlier this year, is believed to be behind the double bombing in Jos, according to Reuters. The twin blasts occurred near a bus station, where a similar bombing killed 118 people in May. A Reuters journalist counted 40 bodies in Thursday's explosions.

A witness to the bombing told the Guardian that police and the military were slow to respond to the explosions. “In the time it took for the police and military to reach the blast site, we had already evacuated two bodies,” said Muhammed Wasse of Jos. “They didn’t help us at all when they arrived. We ordinary people on the streets are dying, and nobody in government is interested.”  

Another witness, Tanko Mohammed, said he saw “a flash of light and heard a loud boom. Afterwards there was debris everywhere and mutilated bodies.”

More than 10,000 people have been killed by Boko Haram-led violence in Nigeria in 2014, and security has become a pressing issue in the country’s national elections, which are  scheduled to be held in February. The twin explosions detonated just hours after Muhammadu Buhari, a former military ruler of Nigeria, announced he would challenge Nigerian President Goodluck Jonathan, the Guardian reported.

In Kano, about 200 miles north from Jos, a 13-year-old girl was arrested Wednesday for allegedly wearing a suicide vest under her hijab. The city has had a spike in suicide bombings, especially from young girls, a source told AFP.

"Her arrest is a huge breakthrough in unravelling the spate of suicide attacks by young girls in the city," the source said. Suspicion was raised because the girl and a male walked into a clinic near where a suicide bombing occurred just hours later.