A series of blasts targeting three buses full of passengers in Nigeria's second city of Kano killed at least 20 people on Monday, a rescue official told AFP.
The Sabon Gari area of the northern city where the explosions occurred was cordoned off by soldiers after bloodied bystanders fled the scene in panic, according to residents.
"I saw three buses on fire. One of them was fully loaded with passengers waiting to leave the station at the time of the blasts. At the moment there are at least 20 dead," said the rescue official who requested anonymity.
"This figure is not the final toll because we are still conducting rescue and the figure may rise," added the official, who asked his name be withheld as he was not authorised to speak to journalists.
Mechanic Tunde Kazeem, who works at the targeted New Road bus station, said the explosion was "followed by billows of black smoke and there was a lot of confusion with people rushing out of the motor park, some of them with blood on their clothes".
While the official confirmed at least two explosions, residents have given figures of up to three, in what may have been a coordinated attack in a city repeatedly targeted by Islamist group Boko Haram.
The station was attacked in January of last year in a blast which wounded several people and which was blamed on Boko Haram, a group that has killed hundreds of people across northern Nigeria since 2009.
The targeted station primarily services passengers heading to the mostly Christian south of Nigeria, Africa's most populous country.