Tripoli: A NATO raid killed Muammar Gaddafi`s youngest son and three grandchildren but the Libyan strongman escaped unhurt in what a regime spokesman on Sunday called a deliberate attempt to assassinate him.
The house of Saif al-Arab Gaddafi "was attacked tonight with full power”, government spokesman Mussa Ibrahim told reporters, announcing the deaths from Saturday night raids.
"The attack resulted in the martyrdom of brother Saif al-Arab Muammar Gaddafi, 29 years old, and three of the leader`s grandchildren."
NATO said it had targeted a command and control centre.
The Libyan leader and his wife were in the building but were not harmed, Ibrahim said, calling the strike "a direct operation to assassinate the leader of this country”.
"The leader himself is in good health; he wasn`t harmed. His wife is also in good health; she wasn`t harmed, (but) other people were injured," he added.
Ibrahim later said intelligence on Gaddafi`s whereabouts appeared to have been "leaked”, adding: "They knew about him being there, or expected him for some reason."
The United States avoided comment on the reported deaths.
"We got calls from Libyans saying someone big was hit," a senior US administration official said on Saturday on condition of anonymity. "But as to who, I have only the same reports as you do."
Gaddafi also lost an adopted daughter in a US air raid in 1986.
British Prime Minister David Cameron called NATO`s targeting policy "in line" with the UN resolution authorising the Libya campaign.
"The targeting policy of NATO and the alliance is absolutely clear. It is in line with UN resolution 1973 and it is about preventing a loss of civilian life by targeting Gaddafi`s war-making machine," he told the BBC.
"It is about targeting command and control rather than particular individuals."
NATO said it had staged air strikes in Tripoli but did not confirm the Libyan claims, and there was no immediate confirmation of the deaths.
A NATO statement said it continued precision strikes against Gaddafi regime military installations in Tripoli overnight, "including striking a known command and control building in the Bab al-Aziziya neighbourhood shortly after 1800 GMT Saturday evening."
Libyan state TV showed flag-waving demonstrators it said were mourning Saif al-Arab`s death.
In the rebel capital Benghazi, overjoyed rebels fired rockets, Kalashnikovs and anti-aircraft guns and set off TNT, rocking the eastern Libyan city with sustained gunfire and explosions.
"They are so happy that Gaddafi lost his son in an air strike that they are shooting in celebration," said Colonel Ahmed Omar Bani, military spokesman of the Libyan opposition Transitional National Council (TNC).
Earlier, Ibrahim took journalists to a heavily damaged house, hinting but not explicitly indicating this was the one in which Gaddafi`s son had died.
Twisted reinforcing steel bars protruded from blasted concrete, part of the roof had caved in, walls had collapsed and a thick layer of dark grey dust covered the grounds.
It appeared improbable anyone inside could have survived.
NATO vowed more strikes, although the commander of Operation Unified Protector stressed that "we do not target individuals”.
"All NATO`s targets are military in nature and have been clearly linked to the... regime`s systematic attacks on the Libyan population and populated areas," said Lieutenant General Charles Bouchard.
The statement said the raids would continue until all attacks and threats against civilians had ceased and until all of Gaddafi`s forces, "including his snipers, mercenaries and paramilitary forces have verifiably withdrawn to their bases, and until there is full, free and unhindered access to humanitarian aid to all those in Libya who need it."
In a Saturday speech on state television, Gaddafi said NATO "must abandon all hope of his departure”.
"I have no official functions to give up: I will not leave my country and will fight to the death," he said.
But he added a conciliatory note: "We are ready to talk with France and the United States, but with no preconditions.”
"We will not surrender, but I call on you to negotiate. If you want petrol, we will sign contracts with your companies -- it is not worth going to war over.”
"Between Libyans, we can solve our problems without being attacked, so pull back your fleets and your planes," he told NATO.
His call was dismissed by the TNC, which has shaped itself into a parallel government in Benghazi, and by NATO.
"The time for compromise has passed," TNC vice chairman Abdul Hafiz Ghoga said. "The people of Libya cannot possibly envisage or accept a future Libya in which Gaddafi`s regime plays any role."
And in Brussels, a NATO official said: "We need to see not words but actions."
Gaddafi`s regime has threatened to attack ships trying to dock in rebel-held Misrata, a crucial conduit for humanitarian aid to the city of half a million, which regime forces have been trying to capture for more than seven weeks.
Thirteen powerful blasts rocked Misrata late on Saturday as NATO warplanes raided targets in areas where pro-Gaddafi forces appeared to be deployed, a journalist said.
Early on Sunday, a salvo of rockets hit the city, but medics said no casualties were reported. Grad rocket strikes were also reported from the port area.
Loyalist forces were pushed back from Misrata by the rebels and air strikes on Monday, with the rebels saying they had secured the port and their next objective was the airport.
But state television said the military had "put the port out of service”, and that humanitarian aid to Misrata should now be delivered "overland and under the supervision of the armed forces”.
In Benghazi, rebels said loyalists had stormed the eastern oasis town of Jalo, several hundred kilometres south, and killed five people.
"It seems Gaddafi is trying to open another front in the south," said one rebel source, while TNC spokesman Jalal al-Gallal worried that the attack was "not a great sign”.