U.S. and European officials Sunday declared a no-fly zone effectively in place over Libya after a second day of massive strikes by air and sea, as Libyan leader Moammar Gaddafi promised “a long, drawn-out war” against foreign forces he called “traitors” and “Nazis.”

“Initial operations have been very effective,” Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, said in an interview on CNN’s “State of the Union” Sunday morning. “We’ve taken out most of his air defense systems and some of his airfields. But there is still a great deal to be done.”

U.S. fighter jets on Sunday mounted attacks on Libyan ground forces advancing on the rebel-held city of Benghazi.

The strikes, which included 15 U.S. fighter jets, were part of a broader mission to halt the advancement of Gaddafi’s military on the rebel strongholds in the eastern portion of the country and to prevent him from using helicopters and fighter jets to pound the rebels.

“Benghazi is certainly not safe from attack but it is certainly under less threat than it was yesterday, and we believe [Gaddafi’s] forces are under significant stress and suffering from both isolation and a good deal of confusion,” said Vice Adm. Bill Gortney, the director of the Pentagon’s Joint Staff.

British and French fighter jets also took part in the strikes on the advancing Libyan forces, Gortney said.

Reporters traveling outside Benghazi on Sunday morning found a graveyard of smoking military vehicles, the remnants of Gaddafi’s force in the area. The overturned armored vehicles and trucks, news agencies reported, had apparently been struck in attacks by U.S., French and British aircraft.

The U.N.-supported mission began Saturday, with French warplanes swooping down on military vehicles and U.S. and British warships raining scores of Tomahawk cruise missiles on Libyan air defenses.

Beyond the attacks on Libyan ground forces, U.S. forces also mounted strikes with satellite-guided bombs on an airfield outside of Misurata, where the Libyan air force maintained fighter jets in hardened shelters.

As of Sunday afternoon the Libyan government had not launched any aircraft over the country and the U.S. military had detected no radar emissions from any of the air defense sites that it had targeted, military officials said.

Despite a plume of smoke around one of Gaddafi’s compounds in Tripoli, U.S. officials said that they were not targeting the Libyan leader. “At this point I can guarantee he is not on the target list,” Gortney said. “We are not targeting his residence.”

The U.S. military is currently taking the lead in the military operations but American commander plan to turn over command to a coalition of other nations in the next few days, Gortney said.

Even after the transfer, U.S. fighter jets, tankers, surveillance aircraft and electronic warfare planes would likely still participate in operations over Libya. The preponderance of the attack forces, however, would come from other nations, Gortney said.

President Obama, in remarks shortly before the missiles flew, said Gaddafi had brought the attacks upon himself by failing to heed international demands for a cease-fire.

“This is not an outcome the United States or any of our partners sought,” Obama said from Brazil on Saturday. “We cannot stand idly by when a tyrant tells his people there will be no mercy.”

Gaddafi claimed that “thousands” of civilians had been killed by the U.S. and European strikes. Speaking on an audio broadcast on Libyan state television, Gaddafi said that the United States and Europe had “proven to the world that you are not civilized, that you are terrorists — animals attacking a safe nation that did nothing against you.”

Mullen said that he had seen “no support” for reports of “any kind of significant civilian casualties” from coalition operations.

The overall commander of the operation, U.S. Gen. Carter Ham, briefed Obama about the operation in a conference call Sunday morning, the White House said. The president, traveling in Brazil on Sunday on a previously scheduled trip, did not publicly mention the military action in Libya.

In his first public remarks in more than a week, Defense Secretary Robert M. Gates said he supported Obama’s approach in Libya and defended his previous skepticism about the operation, saying it was all part of a necessary “spirited debate” that the White House should encourage internally before going to war.

“What I’ve tried to do is really just make clear what is involved in this, and that it is a complex undertaking,” Gates told reporters on his military aircraft shortly after he departed Washington for Russia. “Any president who is contemplating the use of military force should demand a spirited debate, an intense debate, among his advisers on all of the ramifications.”

Gates had not spoken publicly in eight days. On March 12, as he left Bahrain, he said the U.S. military could easily impose a no-fly zone over Libya, but questioned “whether it is a wise thing to do.”

The military assault began less than 48 hours after members of the U.N. Security Council approved a resolution authorizing military force to prevent the annihilation of civilians and rebels who have been under siege by Gaddafi’s military for more than two weeks. The resolution drew broad support from European nations and key Arab allies, coming less than a week after the Arab League for the first time endorsed the use of military force against one of it members.

On Sunday, however, the Arab League secretary general deplored the broad scope of the bombing campaign and said he would call a new league meeting to reconsider Arab approval of military intervention.

“What is happening in Libya differs from the aim of imposing a no-fly zone,” the secretary general, Amr Moussa, said in a statement on the official Middle East News Agency. “And what we want is the protection of civilians and not the shelling of more civilians.”

Jaffe reported from Washington; Whitlock was traveling with Gates. Correspondent Sudarsan Raghavan in Benghazi; staff writer Karen DeYoung in Washington; and staff writer Perry Bacon Jr. in Brasilia contributed to this report.