Tunis, Tunisia — Britain's foreign minister says at least 15 Britons have been killed in the Tunisia beach attack and that the British toll "may well rise."

Tobias Ellwood said Saturday that it was "the most significant terrorist attack on the British people" since July 7, 2005, when suicide bombers struck the London transport network, killing 52 people and wounding hundreds of others.

On Friday, a gunman pulled an assault rifle out of his beach umbrella and killed 38 people in the Tunisian resort of Sousse. The Islamic State group has claimed responsibility for the attack.

Ireland's foreign minister says the government suspects that two other Irish citizens are among the dead in Tunisia in addition to nurse Lorna Carty. Charlie Flanagan said Saturday that "in addition to the fatality made known yesterday, I can confirm that there is grave concern for two other Irish citizens who had been at the scene of the attacks at Sousse, Tunisia."

A special flight, meanwhile, brought Irish tourists home early from Tunisia. Those departing Dublin Airport described scenes of terror in their hotel Friday as panicked guests, some bleeding from wounds or screaming about loved ones shot outside, ran down hotel hallways and pounded frantically on locked doors begging to be let inside. Many described hearing explosions, not just gunfire, and speculated they were grenades.

A major German tour operator says more than 300 customers who had planned to travel to Tunisia this summer have called asking to change their bookings, most of them seeking to change destinations.

TUI said Saturday that other vacationers want to stick to their plans, but didn't give numbers. It said it brought home the first 80 customers from Tunisia on Friday night and another 120 will follow over the weekend — although some of those had been booked to return now anyway.

TUI on Friday offered free cancelations or re-bookings for customers who had booked vacations in Tunisia through Sept. 15. It said it had also canceled planned excursions in Tunisia for the next three days as a precaution.

A scattering of foreign tourists are still wading in the sea on the beach in front of the hotel in Tunisia where a gunman killed 38 people before he was killed by police. Police boats patrolled the waters Saturday while police on horseback rode the beach and some holidaymakers parasailed behind speedboats in the water. A German tourist laid flowers at the edge of the scene of Friday's attack and shed tears for the victims.

While many tourists have left, Welsh couple Angela Chambers and Peter Phillips said they declined their tour operator's offer to take them to the airport last night. "I think we feel safer here than last night going to the airport," said Chambers. Phillips added that "we want to see our holiday out."