Riots broke out in the Kenyan city of Mombasa Monday after gunmen killed a radical Muslim cleric who allegedly supported Somali militant group al-Shabab.

Mombasa police tell VOA that at least two people were killed as protesters battled police officers, burned several churches and blocked off major streets in the port city.

The protesters were demonstrating against the death of Aboud Rogo Mohammed. Witnesses say unidentified gunmen shot and killed the cleric Monday as he drove a van carrying family members.

Kenyan police are investigating the killing.

Aboud Rogo Mohammed was placed on a U.S. sanctions list last month for allegedly recruiting fighters and raising money for al-Shabab.

The U.N. Security Council placed its own travel ban and assets freeze on the cleric, saying he used an extremist group, Al Hijra, as a way of recruiting Swahili-speaking Africans to fight in Somalia.

Al-Shabab is fighting to overthrow Somalia's U.N.-backed government. The militant group is known to have supporters in Kenya, which has a large Somali immigrant community.

Kenyan forces entered Somalia last October to fight al-Shabab, and have since joined the African Union peacekeeping force in the country.