Kenyan officials say more than 30 people have been injured in an explosion in central Nairobi.
Police said late on May 28 that five of those wounded were in critical condition.
Kenyan Prime Minister Raila Odinga called the blast a terrorist attack.
The country has been hit by a string of grenade attacks the police have blamed on Somalia's Al-Qaeda-linked Shabab insurgents or their supporters.
The wave of attacks has killed at least 10 people.
Last month, the hard-line Shabab warned Nairobi of revenge attacks for sending tanks and troops into Somalia in October to fight militants linked to Al-Qaeda.
Based on reporting by AFP and Reuters