Military intervention against Libya may start within "several hours," according to French government spokesman Francois Baroin.
France would join any military operation, such as a no-fly zone, against Libyan leader Muammar Gaddafi, Mr Baroin said.
British Prime Minister David Cameron will meet his Cabinet today and speak to Parliament on Libya after Foreign Secretary William Hague said the UK was ready to enforce a United Nations resolution authorising military action against Gaddafi.
The UN Security Council voted yesterday to ground Gaddafi's air force and to grant military authority to the US and its allies to protect civilians and population centres threatened by his forces. Russia and China were among five abstensions.
"It may start with a mixture of Cruise missiles and air strikes," said Jan Techau, of the Carnegie Endowment for International Peace in Brussels.
The UN's principal policy-making panel voted 10 to 0, with five abstentions, to adopt a resolution that establishes a no-fly zone over Libya, demands a cease-fire and allows "all necessary measures" to protect civilians "excluding a foreign occupation force of any form on any part of Libyan territory".