Six loud explosions rocked Tripoli late on Tuesday within 10 minutes, following powerful strikes 24 hours earlier, including one on Gaddafi's compound, that Libyan officials said killed 19 people and state television blamed on "colonialist crusaders."

French Foreign Minister Alain Juppe said on Tuesday that the NATO bombing campaign was making progress and should achieve its objectives within months. An alliance official said Tuesday's early strike was "the most concentrated to date."

France, Britain and the United States are leading the air strikes, which started on March 19 after the United Nations Security Council authorized "all necessary measures" to protect civilians from Gaddafi's forces as he sought to crush an uprising against his 41-year rule.

The three countries have declared they will keep up the campaign until Gaddafi leaves power. Juppe's upbeat assessment came after the United States said the Libyan leader's departure was inevitable.

France said this week it would deploy attack helicopters to ensure more precise attacks against Gaddafi forces embedded among the civilian population of Libyan cities. Britain said on Tuesday it was considering doing the same.