Muammar Gaddafi's government said it was declaring a unilateral ceasefire in its offensive to crush Libya's revolt, as Western warplanes prepared to attack his forces.
But government troops pounded the rebel-held western city of Misrata, killing at least 25 people including children, a doctor there told Reuters. Residents said there was no sign of a ceasefire.
And in the rebel-controlled east, the government declaration was dismissed as a ruse or a sign Gaddafi was desperate.
"We have to be very cautious. He is now starting to be afraid, but on the ground the threat has not changed," a French spokesman said. Britain, like France a strong advocate of armed action, said it would judge Gaddafi by "actions, not his words."
Turkey, an opponent of military action, said the ceasefire should go into effect immediately.
"We decided on an immediate ceasefire and on an immediate stop to all military operations," Libyan Foreign Minister Moussa Koussa told reporters in Tripoli on Friday, after the U.N. Security Council passed a resolution authorizing military action.
He called for dialogue with all sides. Gaddafi had vowed to show "no mercy, no pity" on Thursday, and rebels pleaded for foreign aid before time ran out.
The ceasefire offer was probably prompted by Gaddafi's realization that air strikes could seriously degrade the Libyan military, said John Drake, senior risk consultant at AKE.
"The Gaddafi regime may be willing to negotiate," he told Reuters. "With talk of strikes against military convoys he may be concerned about a significant attack on his military." Western officials said military action could include France, Britain, the United States and one or more Arab countries.
"Britain will deploy Tornadoes and Typhoons as well as air-to-air refueling and surveillance aircraft," Prime Minister David Cameron told parliament.
"Preparations to deploy these aircraft have already started and in the coming hours they will move to airbases from where they can start to take the necessary action."
City A.M. Reporter