"The entire world has reached a consensus that Colonel Kadhafi and his regime have not only lost their legitimacy but also their credibility," Jalil said in a statement from the rebels' Benghazi bastion late on Saturday.
"I would like to welcome the position taken ... by the G8 where members emphasised the necessity of Colonel Kadhafi's departure," the statement said.
"The position taken by the G8 is reflective of the will of the international community as well as the demands and aspirations of the Libyan people."
On Friday, G8 leaders from Britain, Canada, France, Germany, Italy, Japan, Russia and the US called for Kadhafi to step down after more than 40 years in the face of pro-democracy protests turned full-fledged armed revolt.
Russia at the same time finally join explicit calls for Kadhafi to go.
"The world community does not see him as the Libyan leader," Russian President Dmitry Medvedev said, adding that Kadhafi's departure "would be useful for the country and the Libyan people."
The Libyan regime responded saying any initiative to resolve the crisis would have to go through the African Union.
"The G8 is an economic summit. We are not concerned by its decisions," said Libya's deputy foreign minister Khaled Kaaim.
"We are an African country. Any initiative outside the AU framework will be rejected," he said.
Kaaim confirmed the visit on Monday of South African President Jacob Zuma, without indicating whether Kadhafi's departure would be discussed.
Two sources in Zuma's office, speaking on condition of anonymity, said the talks would focus on Kadhafi's "exit strategy."
NATO carried out fresh bombing raids on the heart of Tripoli's regime on Saturday, the military alliance said, for the fourth successive day targeting Kadhafi's Bab al-Aziziya compound.
The series of blasts caused the collapse of sections of imposing walls around the barracks, which is full of warehouses, although the Libyan authorities say they are empty.
London said the NATO strikes brought down guard towers.
"For decades, Colonel Kadhafi has hidden from the Libyan people behind these walls, spreading terror and crushing opposition," the Ministry of Defence said in a statement, quoting communications officer Major General John Lorimer.
The latest strike "sends a powerful message to the regime's leadership and to those involved in delivering Colonel Kadhafi's attacks on civilians that that they are no longer hidden away from the Libyan people behind high walls," Lorimer said.
Jalil, head of the rebels' National Transitional Council, in his statement accused Kadhafi's forces of attacking rebel-held cities in the Nafusa mountains in western Libya "with heavy artillery, tanks and rocket launchers."
"They continue to shell and besiege the city of Misrata, and also impose arbitrary measures that include random arrests, torture, and raids of homes in the city of Tripoli, Zawiyah, Zwara, and many other cities.
"We witness how Colonel Kadhafi presents initiatives to fool the world and create the illusion that he is in search of peace," Jalil said.
"It is with this in mind that we would like to reconfirm that the basis of any consideration for the resolution of the Libyan crisis, is the removal of the main reason for this crisis, Colonel Kadhafi. As such, there is no room for negotiation until his departure and the departure of his regime."
Elsewhere, rebels fought Kadhafi loyalists near an oil facility in the eastern crossroads town of Ajdabiya, in a clash which left two insurgents dead, rebel commander Jamal Mansur told AFP.
Sporadic clashes were also reported around the rebel-held southern oasis town of Jalo.
The port city of Misrata, meanwhile, was crawling back to normal life, said Fadl Moukadem from Mercy Corps, a non-government organisation.
"A lot of checkpoints have been removed, traffic lights have started working, the city is busy cleaning the sand used to block the roads, and workers are watering the grass in public parks and roundabouts," he told AFP.