A cruise missile smashed into an administrative building inside Libyan leader Moammar Gadhafi's compound in Tripoli overnight Sunday, as international forces kept up their military bombardment. It wasn't clear where Gadhafi was at the time the missile landed.

The Libyan government escorted journalists from at least two major news outlets to the scene to view the damaged building, which stands near the iconic Bedouin tent where Gadhafi has been known to entertain foreign guests.

Half of the multistory building was destroyed, and scraps of metal from the missile lay scattered across the area.

Explosions and anti-aircraft gunfire had erupted in the Libyan capital earlier in the night, signaling another round of coalition air assaults.

The military operation began overnight Saturday to enforce a UN Security Council resolution that called for an immediate ceasefire in the fighting between Gadhafi forces and members of the month-old opposition movement.

The resolution authorized a no-fly zone above the North African country and allowed UN members to use "all means necessary" to prevent attacks on civilians.

Despite the international pressure, Gadhafi pledged Sunday to continue fighting. In a phone call to Libyan state television, he said his weapon depots had been opened up to allow civilians to arm themselves against the outsiders.

"We promise you a long war," Gadhafi said.

During a press conference at the Pentagon on Sunday afternoon, U.S. Navy Vice Adm. Bill Gortney said naval ships had launched 124 cruise missiles at military installations along the Libyan coast, followed by air assaults from French, British and American fighter jets and bombers against Gadhafi ground forces and air defences.

Gortney said the initial assault had been "very effective in significantly degrading the (Libyan) regime's air defence capability," including its ability to launch some surface-to-air missiles.

"We now have the capability to patrol the airspace over Libya, and we are doing just that," he told reporters.

Military forces from Spain, Belgium, Denmark and Qatar are joining the military operation under U.S. command, Gortney said, but a coalition of countries would take over command in the coming days.

Rebel reaction

The coalition air strikes provided some relief to residents of the Benghazi, the capital of the opposition movement that has been seeking to oust the Libyan leader.

On Saturday, at least 120 people were killed in the eastern city of 700,000 as Gadhafi troops staged ground raids and air assaults. But rebel forces said the attacks on Benghazi had since been stunted by international forces.

"Yesterday was a catastrophe," said Salwa el-Daghili, a member of the rebels' governing council. "Today, there is hope -- you can see it on the streets."

U.S. military officials said the international assault would take aim at any Gadhafi forces that were attacking the opposition. And one of their targets was a line of tanks that had been moving towards Benghazi when it was destroyed.

According to the opposition, the coalition attacks also struck an air force complex used by Gadhafi forces near Misrata, the last rebel-held city in the west, and a second air base outside Tripoli.

Meanwhile state television claimed that 48 people died in the U.S. and European strikes and that Gadhafi's supporters were converging on airports as human shields. Neither report could be independently verified.

The Arab League, whose support for a no-fly zone last week helped overcome reluctance in the West for action in Libya, criticized the military operation Sunday. Amr Moussa, the organization's secretary general, said that coalition assaults had gone beyond what his organization backed.

"What happened differs from the no-fly zone objectives," he said Sunday. "What we want is civilians' protection not shelling more civilians."

However, after holding an emergency meeting in Cairo late on Sunday, the Arab League reaffirmed its support for the no-fly zone. France also said Sunday that warplanes from the Arab nation of Qatar would take part in the international military strikes.

Libya's armed forces claimed for a second consecutive day that it had ordered a cease fie. However, its forces appeared again to continue fighting despite the announcement.

U.S. Admiral Mike Mullen, chairman of the Joint Chiefs of Staffs, said the coalition can achieve its goals in Libya but there was a chance that Gadhafi would retain his hold on power.

Mullen said the goals of the military campaign in the North African nation "are limited and it isn't about seeing him go."

The coalition assault began shortly after an emergency military meeting was held in Paris earlier on Saturday.

The summit's 22 participants included UN Secretary-General Ban Ki-Moon, senior representatives from Western nations, and the foreign ministers of Jordan, Morocco and the United Arab Emirates.

With files from The Associated Press