WASHINGTON - US President Barack Obama has said he is confident that Libyan leader Muammar Gadhafi will "ultimately" step down and warned he had not ruled out supplying arms to rebels seeking to oust him.

Obama said the "noose is tightening" around the Libyan strongman, but noted on Tuesday it did not appear yet that Gadhafi was seeking to negotiate an exit from Libya, despite a fierce bombardment of his forces by a Western coalition.

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The president gave interviews to three network television news shows as part of a firm defense of his Libya strategy, which included an address to Americans on Monday and coming appearances by his national security team in Congress.

Obama's comments reflected an apparent attempt by US and allied forces to raise intolerable pressure on Gadhafi and his forces to drive him from power.

"Our expectation is that as we continue to apply steady pressure, not only militarily but also through these other means, that Gadhafi will ultimately step down," Obama said in an interview with NBC.

Obama cautioned in his speech to Americans on Monday, however, that though he would use force to protect civilians, an effort to oust Gadhafi by force would replicate the carnage and financial cost of the Iraq war.

His comments on Tuesday followed a major international conference on next steps in Libya in London where Italian Foreign Minister Franco Frattini said that participants had "unanimously" agreed Gadhafi should leave Libya.

But Frattini said, as yet, no nation had made a formal proposal to offer Gadhafi exile.

Obama told ABC News that those around Gadhafi were being given cause to rethink their positions as his government came under intense outside pressure.

"I think what we're seeing is that the circle around Gadhafi understands that the noose is tightening, that their days are probably numbered, and they are going to have to think through what their next steps are," Obama said.

Obama also confided that he was thinking through the idea of arming opposition rebels in Libya, though had yet to make a final decision.

Agence France-Presse