A car exploded Wednesday in front of a hotel where foreign diplomats and journalists stay while visiting Benghazi, a rare attack in the Libyan rebels' de facto capital.
Jalal el-Gallal, a rebel spokesman, said the blast in the parking lot of the Tibesti Hotel in central Benghazi caused no injuries or deaths. The burning car sent plumes of black smoke into the air.
"It's a cowardly act," he said, adding that rebels assume it was carried out by supporters of Libyan ruler Moammar Gadhafi.
The regime, which has suffered a series of diplomatic setbacks in recent weeks, suffered another blow Wednesday when Gadhafi's oil minister appeared in Rome and confirmed he had defected.
On Thursday, at least three NATO strikes hit targets in the Libyan capital of Tripoli. It was not immediately clear what was targeted.
Opponents of the Gadhafi regime rose up against the Libyan dictator in mid-February, and have wrested control of the eastern half of the north African country. The rebels have set up their de facto capital in Benghazi, Libya's second largest city, and many Western and Arab diplomats who travel there to meet with rebel leaders stay at the Tibesti Hotel.
The rebels insist Gadhafi must relinquish control of the government and leave the country with his sons.
The explosion, which rebel spokesman Mahmoud Shamman said was caused a hand grenade tossed under a car in the hotel parking lot, was the first blast of this magnitude in Benghazi since NATO started its bombing campaign in mid-March and helped drive government troops from the city's gates. Despite months of fierce fighting between rebel forces and Gadhafi's military, Benghazi has been for the most part calm.
Gadhafi "is trying to send a message to tell us he's still there," Shamman told reporters. He's still fighting and he's going to continue fighting. ... We are going to defeat him in the very near future."
President Barack Obama has said that the NATO campaign prevented a massacre of thousands of civilians in Benghazi. Before the airstrikes drove Gadhafi's forces back from Benghazi's outskirts, the Libyan leader was threatening to go door to door to root out rebels and their sympathizers in the city of about 1 million.
Abdul Basit al-Shihaibi, a senior rebel security official, blamed Gadhafi agents for Wednesday's explosion. He said the authorities are reviewing surveillance video from the hotel, and insisted the explosive device was not inside the vehicle but thrown under it.
Ahmed Gulak, a 35-year-old driver, said he was in the hotel when blast occurred. "I heard an explosion and went out to see what happened. I saw two cars on fire," he said, blaming agents of the Gadhafi regime. The blast shattered the windshield of his car.
The explosion set three other vehicles on fire. Ambulances and fire engines quickly arrived at the scene, their blue lights flashing, to put out the blaze. The charred, twisted wreckage of the three cars could be seen in the parking lot.
Hundreds of young men gathered at the scene, snapping pictures with their cell phone cameras and shouting, "Libya is Free, Libya is free." Security forces tried to cordon off the area to let firefighters in to hose down the area.
The attack came as Gadhafi's regime absorbed diplomatic blows.
In Rome, the Libyan oil minister, Shukri Ghanem, said he has defected.
"In this situation you can no longer work, so I have left my country and my work to unite myself with the choice of young Libyans to fight for a democratic country," the ANSA news agency quoted Ghanem as saying.
Ghanem said he left the regime two weeks ago and arrived in Rome on Tuesday. The Italian Foreign Ministry refused to comment. Up to now Libya has insisted that Ghanem was on a business trip. As recently as last week, Libya's Foreign Ministry said he would represent the Gadhafi government at a June 8 OPEC meeting in Vienna.
Ghanem said Libya's oil infrastructure had been badly hurt by the war. "Some wells have been shut down too quickly and without proper procedures, and therefore this situation led to the complete stopping of production," he told reporters. Equipment was stolen or destroyed, meaning it will take "a lot of work" to restart production.
Up to now, oil and gas has accounted for 95 percent of Libya's export income, 25 percent of its gross domestic product and 80 percent of government revenue, according to U.S. government statistics.
The defection followed the departure of eight senior Libyan army officers, including five generals, who were presented to reporters in Rome earlier this week by the Italian Foreign Ministry days after they fled Libya.
Another 13 servicemen loyal to Gadhafi, including a colonel and four commanders, have fled to neighboring Tunisia, the official Tunisian news agency reported. It was the second group of military men to defect to Tunisia this week.
In Brussels, NATO and its partners decided to extend their mission for another 90 days, the military alliance's top official said Wednesday.
"This decision sends a clear message to the Gadhafi regime: We are determined to continue our operation to protect the people of Libya," said NATO Secretary-General Anders Fogh Rasmussen.
In Geneva, a report by the U.N. Human Rights Council charged that Gadhafi's forces have committed war crimes. The 92-page report also found that rebel forces committed "some acts which would constitute war crimes."
The three-member panel based its finds on interviews with 350 people in government and rebel-held parts of Libya, as well as in refugee camps in neighboring countries.
It concluded that government forces committed murder, torture and sexual abuses "as part of a widespread or systematic attack against a civilian population" before and during the conflict that started in February.
"Such acts fall within the meaning of 'crimes against humanity,'" the panel said.
It also found "many serious violations of international humanitarian law committed by government forces amounting to 'war crimes.'"
Associated Press writers Diaa Hadid in Tripoli, Don Melvin in Brussels, Frank Jordans in Geneva and Nicole Winfield in Rome contributed to this report.