French Prime Minister Lionel Jospin says the fight against terror is a "common imperative" for all democracies, and France was committed to supporting a US retaliation.
He claims to have agreed to U.S. requests to open its airspace and offer its naval cooperation in the Indian Ocean, mainly for logistic support.
In a speech to the National Assembly, Jospin expressed France's solidarity with the United States, "the nation to whom we owe our victory over the Nazis."
He also calls for better cooperation between countries to track down terror networks, regardless of different judicial systems or police forces, and the need to shut down the financial networks of terrorists.
"The fight against terror is a common imperative for democracies and must become so for all nations," Jospin said.
The war against terror "is a necessary and methodical act, to which we freely devote all our efforts."
Earlier, France says it will send two military ships to take part in the military operation. LCI television reports the ships concerned were a frigate and a supply ship.