The announcement came after some 24 hours of air bombardment from American, French and British forces aiming to implement a U.N. resolution authorizing the use of force to protect Libyan civilians from government troops.

"The Libyan armed forces ... have issued a command to all military units to safeguard an immediate ceasefire from 9 p.m. (3:00 p.m. ET) this evening," a Libyan army spokesman said.

Earlier in the day, Libyan leader Muammar Gaddafi, using tanks and artillery to try to put down the most serious uprising in his 41 years in power, had said he would give out weapons to his people to help defend Libya against Western forces.