A nine-year-old boy has been killed and at least ten other children have been injured in a grenade attack on a church in Nairobi, Kenya.

The attack on the Anglican church was carried out during a Sunday school service, with police confirming that a grenade was used.

An eyewitness said: "There was worshipping, and we heard a blast from outside on the side of the nursery school...people started stampeding and scampering all over."

Acting police chief Moses Ombati said he believes sympathisers with the Somali militant group al-Shabab were responsible.

Kenya has seen a series of attacks on churches ever since national forces moved into Somalia to fight al-Shabab last year.

Kenyan forces kicked the rebels out of their last stronghold, Kismayo, on Friday.

Red Cross officials said six children in a critical condition had been transferred to Nairobi's main Kenyatta National Hospital for treatment.

A further four children were being treated for minor wounds at a local hospital.