NATO bombards Tripoli in biggest attack yet (VIDEO)

NATO warplanes mounted what appeared to be the most intense bombardment by allied forces since the campaign to oust Muammar Gaddafi began, repeatedly bombing targets around the Libyan capital, Tripoli.

A rapid string of strikes, all within 30 minutes, rattled windows and sent plumes of smoke wafting over the city, the Associated Press reports.

The BBC reports that between 12 and 20 explosions were heard in the early hours of Tuesday, while Reuters quoted a correspondent for Arab news channel Al Arabiya as saying 17 missiles had struck various parts of Tripoli. One column of smoke rose from an area close to Gaddafi’s Bab al-Aziziya compound, suggesting that it might have been a target.

Precision-guided weapons were fired on a vehicle storage facility in the capital that was used to supply government forces and launch attacks on civilian sites, the NATO said on its website.

"This facility is known to have been active during the initial regime suppression of the population in February 2011 and has remained so ever since; resupplying the regime forces that have been conducting attacks against innocent civilians," NATO operations commander Lieutenant-General Charles Bouchard said in a statement

But a Libyan government spokesman, Mussa Ibrahim, said that the barracks of the people's guard had been hit, killing three people and wounding 150.

"The barracks was empty. Most of the victims were civilians living nearby," Ibrahim told journalists on a bus taking them to a hospital shortly after the air strikes, Agence France-Presse reports.

NATO warplanes have been carrying out air strikes on Libya for more than two months since the U.N. authorized "all necessary measures" to protect civilians from Gaddafi's forces.

On Monday, Washington urged Gaddafi to leave Libya as its most senior envoy to date held talks in the rebel capital, Benghazi, Agence France-Press reports.

France and Britain, meanwhile, have decided to send strike helicopters into the battle against Gaddafi.

French Foreign Minister Alain Juppe said Monday the deployment falls within the U.N. mandate to protect Libyan civilians. He said it would take place as soon as possible.

NATO has about 200 aircraft available for its operation in Libya, but it has not yet used helicopters.

Meanwhile, Assistant Secretary of State for Near Eastern Affairs Jeffrey Feltman became the most senior U.S. official to visit Libya since the uprising against Gaddafi began, visiting Benghazi in what the State Department calls "another signal" of America's support for the rebels' National Transitional Council. 

The State Department has called the NTC "a legitimate and credible interlocutor for the Libyan people," VOA reports.

His visit comes a day after the European Union's foreign policy chief, Catherine Ashton, opened an EU office in Benghazi.