At least 37 people have been killed in a series of bomb blasts at bus stations in northeastern Nigeria's Gombe city, sources told Al Jazeera.

The first blast on Wednesday night struck near the Dadin Kowa terminal, prior to a second blast a few minutes later.

Al Jazeera's Ahmed Idris, reporting from the capital Abuja, said that a female suicide bomber was believed to be responsible for the second blast.

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"About an hour later, another bomb attack was reported at the [Dukku bus station]," he said, adding that emergency workers said 37 people have been killed in the explosions, while many more have been injured.

Gombe state police spokesman Fwaje Attajiri confirmed the Dukku blast but did not give a death toll.

Attajiri had no details about the second explosion but one trader, whose shop is near the Dukku bus station, said: "There were two explosions. They happened after I had closed my shop for the day."

"I and others who were around came back and began pulling out bodies. I counted up to 30 dead bodies. I became sick and left."

The blasts bore the hallmarks of Boko Haram, which has previously targeted crowded bus stations, markets, mosques and churches during its bloody six-year campaign.

Gombe city was hit last Thursday, when a series of improvised explosive devices went off in a market, killing 49.

Idris said that the number of Boko Haram attacks has increased over the past two months, since Muhammadu Buhari was sworn in as Nigeria's new president on May 29.

Since then, more than 750 people have been killed in Nigeria alone, according to an AFP news agency count.

Source: Al Jazeera And AFP