Loud explosions followed by barrages of anti-aircraft fire were heard near the Tripoli compound of Muammar Gaddafi on Monday night, an AFP correspondent said, as Barack Obama warned the Libyan strongman he had to leave power.
US policy is that Colonel Gaddafi has to leave power, Mr Obama said, but he stressed the United States would stick to a United Nations mandate during its military action in Libya.
"Our military action is in support of an international mandate from the Security Council that specifically focuses on the humanitarian threat posed by Colonel Gaddafi to his people," Mr Obama told a press conference.
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Mr Obama said as part of the international coalition now enforcing a no-fly zone in Libya, he had "authorised the United States military to work with our international partners to fulfill that mandate."
"Now, I also have stated that it is US policy that Gaddafi needs to go," Mr Obama added after talks in Santiago with Chilean President Sebastian Pinera on the second leg of a Latin America tour.
NATO will be involved in helping to coordinate the next phase of action in Libya, Obama said , adding he expected some kind of transfer of command within days, not weeks.
"Obviously the situation is evolving on the ground,"
"As I said, our initial focus is taking out Libyan air defenses so that a no-fly zone can operate effectively and aircraft and pilots of the coalition are not threatened when they're maintaining the no-fly zone.
"The second aspect of this is making sure that the humanitarian aspects of the mission can be met. But let me emphasize that we anticipate this transition to take place in a matter of days and not a matter of weeks."
He added that he anticipated that: "NATO will be involved in a coordinating function because of the extraordinary capacity of that alliance."
