A smoke was seen over Gaddafi's residential complex

Libyans carry the coffin of two of four rebels, killed during fighting with loyalist troops Fresh explosions rocked Tripoli and its suburbs after NATO said its warplanes had hit a military command centre in the Libyan capital. Two blasts occurred at 00:50 am (2250 GMT) on Sunday in the area housing strongman Muammar Gaddafi's residence in the heart of the capital, followed by others in the city's eastern and southeastern suburbs, an AFP journalist said, adding that planes were flying over the city.
A column of smoke was seen over Gaddafi's residential complex, which had been targeted by NATO warplanes on Saturday, when the transatlantic military alliance confirmed seven strikes and said they hit a military command centre.
Two more explosions were heard in the same area at about midday.
Saturday's attack came after rebel forces said they had lost 16 fighters east of Tripoli and that they infiltrated the capital and attacked a regime command post where a son of the strongman was among officials targeted.
The rebels, who have been fighting to oust Gaddafi for more than five months, said the assault "seriously injured" a high-ranking member of Gaddafi's security forces.
On Thursday, "there was an attack on an operations centre of top regime officials, including Seif al-Islam Kadhafi," National Transitional Council vice president Ali Essawy said after meeting Italian Foreign Minister Franco Frattini in Rome.
He said one person was "seriously injured," identifying the person as a high-ranking security official.
Frattini said the "rocket attack against an operations centre" probably in a Tripoli hotel was aimed at "top officials... including Gaddafi's son Seif, and the head of the secret service, Abdullah al-Senussi."
On Thursday, unconfirmed rumours swirled that rebels in Tripoli had tried to assassinate senior regime members that day.
Since the revolution began in mid-February, a number of Tripoli-based groups have broadcast videos purporting to show acts of civil disobedience in the heavily controlled capital.
Libyan officials denied the attack occurred and denounced as "criminal and unjustified" what they said were NATO raids that killed six guards at a pipeline factory south of an oil plant in the eastern town of Brega.
"There was no attack," government spokesman Mussa Ibrahim told reporters of the rebels' claims that they had attacked a Tripoli command post.
Rebel forces, he said, were losing their battles in the east of the country and to the southwest and were trying "to boost their morale with lies and small victories."
Elsewhere, the rebels said 16 of their men were killed in two days of fighting for Zliten, the last coastal city between insurgent-held Misrata and the capital.
"Sixteen of our fighters have fallen as martyrs and 126 more have been wounded in fighting with loyalist troops in Zliten," a rebel statement indicated, with clashes said to be particularly heavy in the suburb of Souk al-Thulatha.
The insurgents have been trying for weeks to take Zliten, 200 kilometres (120 miles) from Tripoli and 40 kilometres west of Misrata.
The rebels say they have chased the bulk of Gaddafi's forces from Brega in the east and are poised to advance toward the capital from Misrata and their other western enclave in the Nafusa Mountains, southwest of Tripoli.
Rebels at Brega now face "negligible" resistance, military spokesman Colonel Ahmed Omar Bani said.
In the west, the Nafusa campaign is focused on Asabah, gateway to the garrison town of Gharyan on the highway to Tripoli.
Meanwhile, in the remote desert 1,000 kilometres (620 miles) south of Tripoli, Toubou tribal fighters said they had lost control of the oasis of Qatrun.
The strongman's troops swept in from the north on Thursday, forcing rebel fighters out, according to Mohammed Lino in Benghazi, who relayed information gleaned via satellite phone.
At least two people were reported killed and eight wounded.
Lino said Gaddafi's forces had been camped on the north side of the town and rebels in the south, with an estimated 20,000 civilians trapped between them.