* France sends 2 planes, starts humanitarian operation
* PM links aid to effort to prevent influx of immigrants
* Urges EU action to stem migrant influx
(Adds quotes, Italy, concern on migration)
PARIS, Feb 28 (Reuters) - France will send two planeloads of medical aid to the Libyan city of Benghazi, held by opponents of Muammar Gaddafi, marking the start of a humanitarian operation, Prime Minister Francois Fillon said on Monday.
Fillon linked the aid mission to a wider effort by the French government to prevent an influx of immigrants from Libya across the Mediterranean, in the wake of an uprising that has shaken but not broken the rule of Muammar Gaddafi.
France and Italy have both expressed concern that a collapse of organized government in Libya could lead Libyans and migrant workers there to flee to the southern shores of the European Union.
"In a few hours two airplanes will leave for Benghazi at the request of the French government with doctors, nurses, medical equipment, and it will mark the start of a massive humanitarian aid operation for the people in the liberated territories," Fillon said in an interview on RTL.
Opponents of the Libyan leader have taken control of Benghazi, the country's second city, and leading citizens have set up committees to act as a local authority and run services.
Since the uprising against Gaddafi's rule erupted on Feb. 17, he has lost control of the east of the country, where Benghazi is located, and of several other major towns, though his loyalists still control the capital, Tripoli.
"We cannot ignore that there will be large migratory movements," Fillon said. "The best way to avoid them is to help Tunisia succeed, to help Egypt succeed, to make sure the situation in Libya stabilises rapidly."
He also called on the European Union to respond collectively to the risk of uncontrolled migration from North Africa to Europe, echoing the Italian foreign minister's warning of a potential humanitarian disaster.
President Nicolas Sarkozy, who on Sunday night unveiled a government reshuffle aimed at giving more heft to France's foreign policy, linked the Libyan situation and revolutions in Tunisia and Egypt to the threat of uncontrolled immigration.
The centre-right president, whose approval rating is wallowing near record lows, placed his chief of staff Claude Gueant in charge of France's interior and immigration ministries to oversee a tougher approach to immigration before a presidential election in 2012. (Reporting by Nick Vinocur and Vicky Buffery; writing by Nick Vinocur, editing by Tim Pearce)