Updated | Tunisia attack: One gunman was Tunisian, unknown to police

Rafik Chelli, one of Tunisia's leading security officials, told Mosaique FM that the gunman who was shot by security forces was unknown to authorities.

He said the man, from the city of Kairouan, came from the beach hiding his Kalashnikov under an umbrella before opening fire on tourists.

From there he entered the Hotel Imperial through the pool, shooting people as he went.

Chelli said there were many foreigners among the victims but he did not have an exact count of nationalities.

He said authorities had a plan to protect hotels during the month of Ramadan but this was an isolated operation that would have been difficult to counter.

Multiple gunmen have killed at least 27 people in an attack on two hotels on the Tunisian coast, the country's Interior Ministry has confirmed.

Tunisia's Interior Ministry spokesman Mohammed Ali Aroui described the victims as mostly tourists but did not give any nationalities. Local radio has said those killed were mostly German and British, the AP news agency reports.

Hotel guests have barricaded themselves inside their rooms as sounds of gunfire were heard

A tourist hotel in the Tunisian town of Sousse has been attacked, a security source said, adding an exchange of gunfire was reported at the scene.

The resort has been named widely as the El Mouradi Palm Marina though it's possible there are two hotels involved. The extent of the attack is not yet clear.

A holidaymaker said, "I was on the balcony with my sister watching what's going on. We were right by the beach. We heard gunfire but we didn't know what it was.

"Everybody started screaming and running in. My sister was talking to someone who said they had seen somebody shoot someone on a sunbed.

"People were crying and going hysterical. it sounded like a machine gun going off and then there was an explosion.

"They are saying it's going on in the hotel next to us. We have heard people are chasing some men. We've blocked ourselves in our hotel room with a mattress behind door. We are very scared."

Tunisia has been on high alert since March when Islamist militant gunmen attacked the Bardo museum in Tunis, killing a group of foreign tourists in one of the worst attacks in a decade in the North African country.

More details as they emerge