PARIS — France is to triple the size of its elite anti-terrorism unit because the threat from radical groups is believed to have increased since President Sarkozy came to power.

With the newly elected right-wing president pledging to take a more active role in world affairs than his predecessor, Jacques Chirac, the 120 men who currently make up the unit are not considered enough.

In order to deal effectively with potential threats, including bomb attacks, hijackings, and mass hostage taking, the Groupe d’Intervention de la Gendarmerie Nationale, or GIGN, is to become a 380-strong force, rising to 420 by 2010.

This will allow a rapid reaction force of 200 men to be mobilized at any time, rather than just 50. Based in Satory, west of Paris, they will be on constant standby to deal with any attack on French interests anywhere in the world.

“Terrorist threats have increased massively over the past few years, and the unit has to expand to deal with this,” a GIGN source said. Mr. Sarkozy has made the fight against terrorism a priority and was one of the few French politicians to show support for the Iraq war.

Since he came to power last month, the French intelligence agency has received numerous warnings about possible attacks by groups linked to Al Qaeda. Mr. Sarkozy is deeply unpopular with France’s Muslim community of about 5 million. His tough stance during the nationwide riots of 2005 made him a hate figure of disaffected youths of Arab and North African origin.

The GIGN was formed after the taking of hostages by the Palestinian Arab Black September group at the Olympic Games in Munich in 1972. In 1994, it rescued 164 passengers from an Air France plane at Marignane airport, Marseille, which Algerian hijackers intended to fly into the Eiffel Tower.