The dead included 17 foreigners, including people from Japan, Italy, Colombia, France, Poland and Spain. The toll was revised downward from an earlier figure of 20 in what Prime Minister Habib Essid said was the definitive toll.

Mr Essid said the two gunmen had been killed in a police assault and authorities were hunting for possible accomplices. Local media reported it was possible a third gunman was involved Advertisement

Mr Essid said the gunmen, dressed in military uniforms, opened fire on the tourists as they got off a bus to visit the museum, and chased them inside.

Eight people were killed as they got off the bus, an Interior Ministry spokesman said; 10 more were taken hostage and then killed.

State television reported that a Tunisian museum guard was injured and died later of his wounds.

"They just started opening fire on the tourists as they were getting out of the buses ... I couldn't see anything except blood and the dead," the driver of a tourist coach said.

Security forces later advanced into the museum and killed two gunmen in a firefight, state television reported.

European Union Foreign Policy Chief Federica Mogherini said Islamic State militants, who have become particularly active in neighbouring Libya, were behind the attack.

"The EU is determined to mobilise all the tools it has to fully support Tunisia in the fight against terrorism," she added.