NAIROBI, Kenya (AP) - There's been an explosion on a bus in Kenya's capital.
Police and the Red Cross say at least five people were killed and more than two dozen injured.
Kenya has been hit by a string of grenade attacks in recent months blamed on sympathizers of al-Shabab, Somalia's Islamist extremist rebels linked to al-Qaida.
Al-Shabab has vowed to carry out attacks on Kenya because it sent troops into Somalia last year to fight the rebels, who are considered a threat to Kenya's security because they have been blamed for kidnapping foreign tourists and aid workers in Kenya.
Copyright 2015 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.