Five powerful blasts rocked Tripoli late Sunday after three waves of explosions during the day, as warplanes overflew the city which has been the target of intense NATO raids for the past two weeks.
In a statement, the military alliance said it conducted "intensive and sustained strikes against pro-Kadhafi facilities in Tripoli throughout the day and night," including command and control centres.
"We will continue to erode (the Kadhafi regime's) foundations until the violence against the Libyan population ends," it quoted Lieutenant General Charles Bouchard, commander in chief of the NATO mission, as saying.
NATO also reported strikes against three military vehicles in the vicinity of the strategic oil town of Brega and an armoured vehicle near rebel-held Misrata, Libya's third city.
The latest salvos came as Russian mediator Mikhail Margelov prepared to head to the Libyan rebel stronghold of Benghazi after Moscow voiced concerns about the NATO operation sliding towards a land campaign.
Margelov, President Dmitry Medvedev's Africa envoy, told Russia's RIA Novosti news agency he would meet rebel leaders including Mustafa Abdul Jalil, head of the National Transitional Council that controls eastern Libya around Benghazi.
His spokesman in Moscow said he would arrive in Benghazi on Tuesday morning and that the trip would exclude a visit to the Libyan capital.
Medvedev announced at the G8 summit last month that he would be sending the envoy to Libya, as Moscow seeks to present itself as a potential mediator and expresses growing alarm over the continued conflict.
"A drawing out of the armed conflict will worsen the humanitarian situation not only in Libya but also in neighbouring states that are taking on Libyan refugees," Margelov told RIA.
"This all threatens a dangerous destabilisation of the situation in the region," he said.
Moscow has expressed alarm as NATO's air campaign to enforce a UN-mandated no-fly zone to protect civilians entered a new phase with the deployment of British and French attack helicopters over the weekend.
"(NATO is) using attack helicopters on land targets, which is in my view the last but one step before the land operation," said Russian Deputy Prime Minister Sergei Ivanov on Sunday
British Foreign Secretary William Hague on Sunday defended the use of the helicopters and ruled out putting forces on the ground, saying NATO would stick to the terms of UN Resolution 1973 passed in March to protect civilians.
"This is not mission creep, changing the nature of the mission, this is intensifying what we are doing in order to make this mission a success," he said after stressing that no deadlines would be set on the mission.
The rebel leader Jalil had praised the deployment of attack helicopters, saying: "We welcome any action that could precipitate the end of (Moamer) Kadhafi's regime."
Britain said on Sunday its Apache helicopters unleashed "Hellfire missiles" to destroy a multiple rocket launcher operated by Kadhafi forces near the eastern oil hub of Brega.
British Tornado strike warplanes separately joined other NATO aircraft in a "major strike on a large surface-to-air missile depot" in Tripoli, Major General Nick Pope, spokesman for the Chief of Defence Staff, said in a statement.
US Defence Secretary Robert Gates said meanwhile that it was only a matter of time before Kadhafi's aides abandoned him.
"It's only a matter of time (before he falls)," Gates said. "I don't think anyone knows how long. But I think you see signs the regime is getting shakier by the day.
"It's just a question when everybody around Kadhafi decides it's time to throw in the towel and throw him under the bus," he said on a visit to Afghanistan.
Elsewhere, Switzerland's justice ministry said Monday it approved legal action to prosecute the Libyan regime for holding Swiss citizens Rachid Hamdani and Max Goeldi hostage.
"The Federal Council authorises the opening of a penal procedure against the Libyan regime... over hostage taking and extortion and blackmail in the case of the two Swiss citizens Rachid Hamdani and Max Goeldi," the ministry said in a statement.
The two men were blocked from leaving Libya in a tit-for-tat action after the brief arrest in Switzerland of one of Kadhafi's sons in July 2008 over mistreatment allegations by domestic staff.