President Barack Obama authorized limited military action against Libya Saturday, saying Moammar Gadhafi's continued assault on his own people left the U.S. and its international partners with no other choice. The Pentagon said 112 cruise missiles were launched from US and UK ships and subs, hitting 20 targets.
Obama said military action was not his first choice.
"This is not an outcome the U.S. or any of our partners sought," Obama said from Brazil, where he is starting a five-day visit to Latin America. "We cannot stand idly by when a tyrant tells his people there will be no mercy."
A senior military official said the U.S. launched air defenses Saturday with strikes along the Libyan coast that were launched by Navy vessels in the Mediterranean. The official said the assault would unfold in stages and target air defense installations around Tripoli, the capital, and a coastal area south of Benghazi, the rebel stronghold.
Obama declared once again that the United States would not send ground forces to Libya, though he said he is "deeply aware" of the risks of taking any military action.
Earlier in the day, Obama warned that the international community was prepared to act with urgency.
"Our consensus was strong, and our resolve is clear. The people of Libya must be protected, and in the absence of an immediate end to the violence against civilians our coalition is prepared to act, and to act with urgency," Obama said.
Top officials from the U.S., Europe and the Arab world meeting in Paris, where they announced Saturday immediate military action to protect civilians caught in combat between Gadhafi's forces and rebel fighters. American ships and aircraft were poised for action but weren't participating in the initial French air missions.
As the military action was announced, French fighter jets swooped over Benghazi, the opposition stronghold that was stormed by Libyan government forces earlier Saturday, in defiance of a proclaimed ceasefire.
France, Britain and the United States had warned Gadhafi Friday that they would resort to military means if he ignored the U.N. resolution demanding a cease-fire.
The United States has a host of forces and ships in the area, including submarines, destroyers, amphibious assault and landing ships.
The U.S. intended to limit its involvement -- at least in the initial stages -- to helping protect French and other air missions by taking out Libyan air defenses, but depending on the response could launch additional attacks in support of allied forces, a U.S. official said. Both officials spoke on condition of anonymity because of the sensitivity of military operations.
AP National Security Writer Robert Burns contributed to this report from Washington