An explosion happened on Wednesday at a busy shopping mall in Abuja, Nigeria, right around the time when traffic in the mall is heaviest. The mall is also surrounded by two other shopping centers. Many surrounding cars have also been involved in the explosion.

Police spokesman Frank Mba told reporters that the numbers that have been confirmed so far are 21 dead and 17 wounded.

Although the reason for the bombing has not yet been confirmed, many suspect that the perpetrator of the bombing is Boko Haram, a group which has been involved in two bombings in Nigeria in the past 10 weeks.

Boko Haram has been declared a terrorist group by the U.S. government in 2013 for its frequent attacks on civilians. The term Boko Haram translated roughly means “Western education is forbidden,” and the group started initially as an opposition toward Western education in the country.