Powerful explosions have ripped through two passenger buses in the Kenyan capital Nairobi, causing casualties, the Kenyan Red Cross and police said.

At least three people are believed to have been killed in the blasts, Reuters news agency reported.

Kenyan media reports said that explosive devices had been thrown at the buses from the side of the road.

The buses blew up on Sunday in the Thika Road area close to the city centre.

AFP news agency reported that at least 27 people have been wounded in the blasts, quoting police officials.

There was no claim of responsibility

Images on Kenyan television showed a large red passenger bus with a large hole ripped out of its side, and a green bus with its roof and sided buckled by an explosion.

It came a day after four people were killed when attackers threw an explosive device at passengers at a bus station in Mombasa, and also targeted a luxury hotel in the coastal city.

Kenya has blamed similar attacks on the al-Qaeda-linked Somali group al-Shabab, which killed at least 67 people at the Westgate shopping mall in Nairobi last September.

Source: Agencies