Holiday operator Thomas Cook is evacuating around 1,800 British and Irish tourists and 2,000 Germans from Tunisia in light of political unrest there, the company said.
Tunisia has been shaken by violent protests against unemployment and poverty in the past month, in which protesters have died in clashes with police.
Although there have been no specific problems for our holidaymakers, their well-being is our primary concern so, as a precaution, we've taken the decision to bring them back to the UK as soon as we can, using our fleet of aircraft today, Thomas Cook said in a statement on Friday.
Thomas Cook said its next planned departures for Tunisia, which were due to take place on Sunday, had been cancelled following advice from the Foreign Office.
The British Foreign Office - whose travel advice many tour operators follow - changed its advice on Tunisia on Thursday, advising against all but essential travel to the country.
It cited the violence in areas including the capital Tunis and places such as coastal resort Hammamet and desert town Douze, both popular with tourists.
Britain's Foreign Office Minister of State Jeremy Browne said the government was not yet urging Britons to leave.
We are saying to people who are already there that they should keep in touch with their tour operators. We are not yet in a position where we're recommending people leaving as an emergency, here and now, he told BBC radio.
Thomas Cook said it was currently reviewing the situation ahead of its next planned departures on January 19 and said it would contact customers due to flight out on that date shortly.
Rival TUI Travel, which owns Thomson and First Choice, said it did not see the need for a full evacuation of customers from Tunisia although it is organising aircraft for those customers wishing to return home.
The safety of our customers and staff in Tunisia is our primary concern and we are continuously reviewing and monitoring the situation. Should the situation change, we will take immediate action and update customers, it said.
In light of the Foreign Office advice, TUI Travel said it was also cancelling its scheduled flights to Tunisia on Sunday. No decision has yet been made on flights due to depart after that date, it said.
Shares in Thomas Cook were down 0.3 percent to 199 pence at 1230 GMT with TUI Travel shares up 0.5 percent to 263.9 pence. TUI AG shares were down 3 percent to 10.16 euros.