By Lin Noueihed
TRIPOLI (Reuters) - Libya said Sunday Muammar Gaddafi's youngest son and three grandchildren were killed in a NATO air strike and Britain said that while it was not targeting the leader, it was homing in on his military machine.
Libyan government spokesman Mussa Ibrahim said Gaddafi was unharmed and in good health despite what he called "a direct operation to assassinate the leader of this country."
The deaths have not been independently confirmed.
But they will be sure to heap pressure on NATO from critics who say it is overstepping a U.N. mandate to protect Libyan civilians and could trigger a backlash against the West and a renewed government push against rebels supported by the strikes.
Britain and Italy's embassies in Tripoli were attacked after Gaddafi loyalists were shown on Libyan television vowing vengeance following the air strike.
Britain expelled the Libyan ambassador and Italy condemned the attack on its embassy as a grave and vile act.
Most Western countries closed their embassies in Tripoli before the NATO military intervention began several weeks ago.
Libyan officials took journalists to a Tripoli house that had been hit by at least three missiles. The roof had collapsed in places. Glass and debris covered the lawns and what appeared to be an unexploded missile lay in one corner.
"What we have now is the law of the jungle," Ibrahim said. "We think now it is clear to everyone that what is happening in Libya has nothing to do with the protection of civilians."
Libya's civil war, which grew out street demonstrations for greater political freedoms that have rippled across the Arab world, has reached stalemate in recent weeks.
NATO DENIES GADDAFI TARGET
NATO denied targeting Gaddafi, or his family, but said in a statement it had launched air strikes on military targets in the same area of Tripoli as the bombed site seen by reporters.
Ibrahim said Gaddafi's youngest son, Saif al-Arab, was killed in the attack. Saif al-Arab, 29, is one of Gaddafi's less prominent sons, with a limited role in the power structure. Ibrahim described him as a student who had studied in Germany.
Al Arabiya Sunday broadcast footage taken from Libyan Jamahiriyah TV which it said were the bodies of Saif al-Arab and the three children -- two 2-year-olds and a five-month-old. They were wrapped in green cloth with their faces covered in white.
"NATO continued its precision strikes against regime military installations in Tripoli overnight, including striking a known command and control building in the Bab al-Aziziyah neighborhood shortly after 1800 GMT Saturday," NATO said.
NATO's commander of Libya operations, Canadian Lieutenant-General Charles Bouchard, said the target was part of a strategy to hit command centres that threaten civilians.
"All NATO's targets are military in nature ... We do not target individuals," he said in a statement. "I am aware of unconfirmed media reports that some of Gaddafi's family members may have been killed. We regret all loss of life."
Any appearance of an assassination attempt against Gaddafi is likely to lead to accusations that the British- and French-led strikes are exceeding the provisions of the U.N. resolution to protect civilians.
British Prime Minister David Cameron declined to comment on what he also called the "unconfirmed report."
But he told BBC television: "The targeting policy of NATO and the alliance is absolutely clear. It is in line with U.N. Resolution 1973 and it is about preventing a loss of civilian life by targeting Gaddafi's war-making machine. So that is obviously tanks and guns, rocket launchers, but also command and control as well."
The French Foreign Ministry said: "France is following its mandate from the U.N. Security Council and there is no question of regime change or targeting individuals in the resolution."
Venezuelan President Hugo Chavez, a long-time ally of Gaddafi, called the attack attempted murder.
FIGHTING IN WEST
Gaddafi, who seized power in a 1969 coup, is fighting an uprising by rebels who have seized much of eastern Libya. He describes the rebels as religious extremists and Western agents who seek to control Libya's oil.
Saturday night's attack appeared to be the second NATO strike near to Gaddafi in 24 hours. A missile struck near a television station early Saturday when the Libyan leader was making an address in which he said he would never step down and offered talks to rebels.
The rebels say they cannot trust Gaddafi.
Gaddafi's daughter was killed in a U.S. air strike in 1986, ordered after a bomb attack on a West Berlin discotheque killed two U.S. servicemen. Washington linked Tripoli to the attack.
Tripoli has declared a sea blockade on the besieged western outpost of Misrata, potentially stopping the rebels from sending weapons and humanitarian supplies in from their eastern heartland. An International Organisation for Migration ship, the Red Star One, was waiting offshore to deliver aid and evacuate migrants.
A rebel spokesman reported more shelling in Misrata.
"The bombardment started last night. It is still going on," the spokesman, called Reda, told Reuters by telephone. "The random bombardment targeted residential areas and the port area. I can hear explosions now."
Rebel spokesman Ahmed Hassan said later that the Libyan army was shelling where an aid ship was trying to unload. Libyan TV said government forces were trying to stop a NATO arms delivery to "armed criminal gangs."
A third rebel spokesman said government forces and rebels were fighting for control of the airport near Misrata.
Pockets of fighting continued elsewhere in the west.
Government forces were bombarding Zintan with rockets to try to advance on the rebel-held city southwest of Tripoli, and the rebels said NATO was bombing Libyan army positions nearby.
Loyalists' artillery fire also landed in the Tunisian border town of Dehiba after fighting on the Libyan side of the border.
A rebel spokesman and an oil official said an air strike destroyed a Gaddafi convoy after his forces killed five civilians in fighting in the eastern towns of Jalu and Awlijah.
(Additional reporting by Tarek Amara and Abdelaziz Boumzar in Dehiba, Deepa Babington and Michael Georgy in Benghazi, Matthew Tostevin in Tunis, Justyna Pawlak in Brussels; writing by Louise Ireland; editing by Mark Heinrich)