Pro-Gaddafi forces on Tuesday launched fresh air raids on Libya’s rebel-held eastern oil port of Ras Lanuf in a bid to prevent his opponents from advancing towards the capital Tripoli, amid mounting global calls for enforcing a no-fly zone over the country.

68-year-old Muammar Gaddafi’s warplanes dropped missiles near rebel positions in the desert east of Ras Lanuf, reports reaching here said, adding there were no casualties or damage.

The Libyan ruler’s supporters moved eastward in an effort to push the rebels back and recapture fallen towns, with reports emerging that they have taken the central town of Bin Jawad, according to Al-Jazeera.

There has also been fierce fighting in the eastern city of Misurata, located between the capital Tripoli and Gaddafi’s hometown of Sirte.

As the uprising against Gaddafi’s 41-year rule entered 22nd day, there were reports that the embattled leader had sent a representative to make a proposal to the opposition’s so-called “National Council” based in Benghazi.

It is said he wanted guarantees for his and his family’s safety and immunity from prosecution.

But, Libyan state television denied the reports that Gaddafi tried to strike a deal with the rebels that would have seen him step down.

In Washington, US President Barack Obama tried to raise pressure on Gaddafi further by talking about “a range” of possible options, “including potential military options” against the embattled Libyan leader, even as Britain and France were drafting a UN resolution that would establish a no-fly zone.

Obama said the US would stand with the Libyan people as they face “unacceptable” violence.

“I want to send a very clear message to those who are around Colonel Gaddafi: It is their choice to make how they operate moving forward, and they will be held accountable for whatever violence continues to take place there,” Obama said.

“In the meantime, we’ve got NATO, as we speak, consulting in Brussels around a wide range of potential options, including potential military options, in response to the violence that continues to take place inside of Libya,” he added.

William Hague, the UK foreign secretary, said Britain is “working closely with partners on a contingency basis on elements of a resolution on a no-fly zone”.

“There should be a demonstrable need that the whole world can see, there must be a clear legal basis for such a no-fly zone and there must be clear support from the region… as well as from the people of Libya themselves,” he said.