Updated

The mayor of a small city in northern Colombia says 31 people were wounded when an explosive device was thrown into a crowded nightclub.

Caucasia Mayor Oscar Anibal Suarez says three women were seriously injured in the pre-dawn attack Friday at the Bora Bora nightclub. Suarez says the rest of the victims suffered only minor injuries.

About 70 people were at the club when the device was thrown from a motorcycle and set off a stampede among panicked club patrons.

The mayor says police arrested a man and woman as suspects in the attack. Their names haven't been released. He says the attack appears to stem from a battle among local drug gangs for control of the city north of Medellin.