Islamist gunmen have killed eight people in a night-time raid on Kenya's coast in a second day of violence.

The latest attacks come just 24 hours after an initial attack left 50 dead.

The Red Cross says al Shabaab attacked the area of Poromoko leaving at least eight dead but the militants claimed they killed as many as 20 people - mostly police.

The area is close to Mpeketoni, on the coast between the Mombasa and Somali border where the extremists murdered 50 people in a raid on Sunday night.

Al Shabaab military operations spokesman Sheikh Abdiasis Abu Musab threatened the onslaught would continue and said, "We raided villages around Mpeketoni again last night. Our operations in Kenya will continue."