Washington, March 15 (DPA) US President Barack Obama and Danish Prime Minister Lars Loekke Rasmussen discussed options to "tighten the noose" on Libyan leader Muammar Gaddafi at a White House meeting.

"We both share the view that Mr. Gaddafi has lost legitimacy and he needs to leave, and that we as an international community have to speak firmly against any violence that's directed at civilians," Obama said Monday.

The US and European Union have called on Gaddafi to resign even as his forces have launched an offensive to retake territory that had been seized by rebels based in eastern Libya.

The US and its NATO allies have not ruled out military action, including establishing a no-fly zone to ground Gaddafi's air force. The US and EU have enacted sanctions against Gaddafi's regime to further isolate him and pressure him to leave office.

"He should be history. He has lost his legitimacy," Rasmussen said. "And I think its important that the international society examine all options to protect the Libyan people."

Obama and Rasmussen also discussed the conflict in Afghanistan. Denmark has long been a US ally in the conflict, and has been engaged in some of the heaviest fighting.

"Of special importance has been our appreciation of the sacrifices that have been made by Danish troops in Afghanistan, and the extraordinary leadership that Denmark has shown as part of" the international coalition.