LONDON — The United States, France and Britain told Libya's leader Moammar Gadhafi to withdraw his troops from formerly rebel-held areas and halt any attacks on civilians there, as warplanes that could strike this north African country moved into the Mediterranean region.
President Barack Obama went even further, saying that if the Libyan leader did not stand down the United States would join other nations in launching military action against him.
Libya, meanwhile, said it stopped its military advance on rebel forces and invited monitors to observe the ceasfire.
The United States, Britain and France — backed by unspecified Arab countries — told Gadhafi in a statement late Friday that a cease-fire must begin "immediately," the French presidential palace said.
The statement called on Gadhafi to end his troops' advance toward the eastern city of Benghazi, and pull them out of Misrata, Adjadbiya and Zawiya. It also called for the restoration of water, electricity and gas services in all areas, saying Libya's population must be able to receive humanitarian aid.
"This is not negotiable," the statement said.
In Tripoli, Libya's deputy foreign minister, Khaled Kaim, invited Germany, China, Turkey and Malta to send observers to monitor the cease-fire, which he said was holding. "The cease-fire for us means no military operations whatsoever, big or small," he told reporters.
British Prime Minister David Cameron, one of the most enthusiastic backers of a no-fly zone, said Britain would send Typhoon and Tornado fighter jets to air bases "in the coming hours" so they would be in position to stop Moammar Gadhafi's forces mounting air strikes against rebels based in the eastern city of Benghazi.
"The clock is ticking and we must be ready to act quickly," Cameron said, adding that Gadhafi must prove he was serious about a cease-fire to avoid military strikes.