At least 10 people have been wounded in a grenade attack at a restaurant south of Kenya's coastal city of Mombasa, according to local police.

Two men riding a motorcycle hurled a grenade towards customers in the crowded Tandoori restaurant on Thursday, Evans Achoki, Kwale county commissioner, said.

At least one person was seriously wounded and has undergone surgery at a nearby hospital, he said.

"We had an explosion at the bar and about 10 people were injured," Jack Ekakuro, the local police chief in Diani, a popular coastal tourist resort town, said.

Kenya has been the scene of multiple attacks since the country sent its military to Somalia in 2011 to combat al-Qaeda-allied rebels of al-Shabab.

The group claimed responsibility for the September 2013 attack on Westgate Mall in the capital, Nairobi, that killed at least 67 people.

It is not yet clear who was responsible for Thursday's attack, but police are conducting an investigation.

Source: Agencies