President Obama's national security adviser says actions taken by an international coalition against the regime of Libyan leader Muammar Qadhafi are necessary to prevent a humanitarian catastrophe.

National Security Adviser Tom Donilon told reporters that the aim is to stop troops loyal to Qadhafi from any further attacks on civilians across Libya. Donilon is traveling with the president, who is on a five-day, three-nation trip to Latin America.

"The president authorized the armed forces of the United States to begin a limited military action in Libya in support of an international effort to support and protect Libyan citizens," Donilon said at a March 20 briefing in Rio de Janeiro, Brazil.
"That had three … elements to it, which are … limited in duration and scope: one, to set the conditions for the enforcement of a no-fly zone in Libya; second, to take actions to protect citizens in Libya from attack; and third, to set the conditions and open up the ability for humanitarian assistance to reach citizens in Libya," Donilon said.

In an agreement with international partners, the United States is providing a set of its unique military assets -- sea-launched Tomahawk cruise missiles and electronic jamming -- at the front end of the effort, he said. That effort is being coordinated by General Carter Ham, commander of the U.S. Africa Command based in Stuttgart, Germany.

"That's allowed us in the first 24 hours of this operation to take very aggressive action against air-defense systems in Libya … [and] air assets that the regime possessed that were being used against civilians," Donilon said.

Ham told reporters at a Pentagon briefing in a videoconference from his Stuttgart headquarters March 21 that U.S. and British navy forces in the last 24 hours had launched 12 more Tomahawk cruise missiles at Libyan command-and-control facilities, a Scud missile battery, and an air-defense site that had previously been attacked. On March 19 at the outset of coalition operations, U.S. and British navy ships in the Mediterranean Sea fired 112 Tomahawk cruise missiles at targets inside Libya.

"Coalition air forces from France, Spain, Italy, Denmark and the United Kingdom flew missions to sustain the no-fly zone over Benghazi to protect civilians from attack by regime ground forces and to conduct further reconnaissance," Ham said.

"Air attacks have succeeded in stopping regime ground forces from advancing to Benghazi and we are now seeing ground forces moving southward from Benghazi," he said. "I assessed that our actions, to date, are generally achieving the intended objective."

Since the coalition airstrikes and cruise missile strikes began March 19, U.S. and international partners said they have not observed Libyan military aircraft operating, and there has not been any indication of the regime's long-range air-defense radar operating.

Donilon said there has been a significant effort by coalition forces to protect Benghazi and lessen the threat posed by the regime's armored and ground forces that were on the outskirts of the eastern coastal city of more than 700,000 people. He said the specific short-term goal of the military operation is to protect civilians, which is what the United Nations sought in its March 17 resolution.

In the next phase of the operation, which involves maintaining a no-fly zone over Libya and preventing any attacks on civilians, the United States' role will change and events will be coordinated by coalition partners using NATO machinery, Donilon said.

The unique assets the United States can provide include electronic jamming, intelligence support and fueling support.

U.N. Security Council Resolution 1973 was approved by the council by a 10-0 vote with five abstentions on March 17. It authorizes the use of all means necessary including a no-fly zone to stop the military forces of the Libyan regime from attacking the Libyan people.