At least four people have been killed and several injured by a grenade attack on a bus in the Kenyan capital, Nairobi, the interior ministry says.
The blast hit the 32-seater bus near the Eastleigh suburb, which is home thousands of ethnic Somalis.
The ministry said such attacks would "not be tolerated"
The Eastleigh area has suffered several attacks in the past, blamed by officials on Somalia's al-Qaeda-linked al-Shabab militant group.
The group was behind the siege at the Westgate shopping centre in Nairobi earlier this month in which 67 people died.
"A group of assailants threw a grenade into a bus with 32 seats," the interior ministry said on its Twitter account.
"The attack is an unfortunate and cowardice incident which will not be tolerated," it said, appealing for information from the public.
Police said the bus had been close to a girls' school when it was hit on Sunday afternoon.
The Kenyan Red Cross said on its Twitter feed that 15 injured people had been taken to hospital.
Last year, Kenya sent its troops to fight al-Shabab in Somalia. They have now joined the 18,000-strong African Union (AU) force supporting the UN-backed government.
Reproduced under licence from BBC News © 2013 BBC