In a further sign of Gadhafi's faltering hold, two air force pilots — one from the leader's own tribe — parachuted out of their warplane and let it crash into the eastern Libyan desert rather than follow orders to bomb an opposition-held city.

International momentum was building for action to punish Gadhafi's regime for the bloody crackdown it has unleashed against the uprising that began Feb. 15.

President Barack Obama said the suffering and bloodshed in Libya "is outrageous and it is unacceptable," and he directed his administration to prepare a full range of options, including possible sanctions that could freeze the assets and ban travel to the U.S. by Libyan officials.

French President Nicolas Sarkozy raised the possibility of the European Union cutting off economic ties.

Another proposal gaining some traction was for the United Nations to declare a no-fly zone over Libya to prevent it using warplanes to hit protesters. U.N. High Commissioner for Human Rights Navi Pillay said that if reports of such strikes are confirmed, "there's an immediate need for that level of protection."

Italy's Foreign Minister Franco Frattini said estimates of some 1,000 people killed in the violence in Libya were "credible," although he stressed information about casualties was incomplete. The New York-based Human Rights Watch has put the death toll at nearly 300, according to a partial count.

In Tripoli, Gadhafi's stronghold, protest organizers called for new rallies Thursday and Friday, raising the potential for a more bloody confrontation.