Watch: Islamic State attackers terrify tourists at Tunisia beach, 39 killed

Sousse: A gunman disguised as a tourist opened fire at a Tunisian hotel on Friday with a rifle he had hidden in an umbrella, killing 39 people including Britons, Germans and Belgians as they lounged at the beach in an attack claimed by Islamic State.

It was the worst attack in Tunisia's modern history and the second major massacre this year following the Islamist militant assault on Tunis Bardo museum when gunmen killed 21 foreign visitors.

A health ministry statement said British, German and Belgian nationals were among the 39 dead. The health minister told French radio 36 others were wounded in the shooting.

At least five British citizens were among the dead, Britain's Foreign Minister Philip Hammond said. Ireland's foreign ministry said at least one Irish citizen was killed.

Tunisia, which has been hailed as a model of democratic transition since its 2011 'Arab Spring' uprising, is one of the most secular countries in the Arab world. Its beach resorts and nightclubs on the Mediterranean are popular with foreigners.

Islamist jihadists have attacked North African tourist sites before, seeing them as legitimate targets because of their open Western lifestyles and tolerance of alcohol.

Irishwoman Elizabeth O'Brien, who was staying at a neighbouring hotel with her two sons, said there was panic on the beach when gunfire erupted.

"I honestly thought it was fireworks and then when I saw people running... I thought, my God, it is shooting," she told Irish radio station RTE. "The waiters and the security on the beach started to say 'Run, run, run!'"