"We have decided to search at 100 percent all the carry-on luggage on flights to the United States, the United Kingdom and Israel," he said after an emergency security meeting to fight the terrorist at the Prime Minister's office.

"We'll also make selective examination and reinforce the patrol on the Eurostar (high-speed rail service linking Great Britain with France and Belgium), in all French railway stations and airdromes," he added, noting that these steps had been decided at the request of Prime Minister Dominique de Villepin.

He also said that dogs would be used to detect explosives in railway stations and airports.

He noted that it did not seem currently that there were suspects branching out in France and that more concrete elements on the modus operandi of the terrorist clan would be available in two or three days, adding that they seemed to be of Pakistani origine.

He also said that the terrorism alert level in French airports would remain unchanged at "red", the third highest on a four-color scale.

Sarkozy cut short his holidays after the announcement of a foiled bomb plot in Britain to chair a meeting Thursday afternoon with national police chiefs and top officials from the intelligence and national security services.

He then briefed Prime Minister and Foreign Minister Philippe Douste-Blazy during the meeting at Villepin's office on fight against terrorism.

Some 50 flights from France to London were canceled Thursday, including 10 flights of French airline Air France, 25 from Paris's main airport Charles de Gaulle, three from Orly and eight from the Mediterranean city of Nice, leaving hundreds of passengers stranded, according to French authorities.