At least four people have been killed and six wounded after armed men attacked a restaurant in a Kenyan town on the border with Somalia, a local official has said.

"Four people died on the spot, while six others were rushed to hospital," Garissa County Commissioner Mohamed Maalim told the AFP news agency.

A motive and the identity of the attackers was not immediately known, he said.

Speaking on condition of anonymity, a police officer in Garissa said five people had died in Wednesday's attack.

"Gunmen just shot inside the hotel and fled," the officer said.

Kenya has been hit by a wave of grenade and gun attacks, often blamed on sympathisers of Somalia's al-Shabab fighters, since its army went into Somalia last year to fight against the armed group.

Garissa has been one of the flashpoints since the Kenya began operations last October. 

Five police were killed in Garissa last November and in early January four people, including three police officers, were wounded when a grenade was hurled at a police vehicle.

Source: Agencies