Libyan rebels tighten grip on Tripoli; Panetta says end is near for Gaddafi (VIDEO)

Libya's opposition rebels have further isolated the capital Tripoli overnight, and claim they could end the almost half-century rule of Muammar Gaddafi by the end of this month.

And U.S. Defense Secretary Leon Panetta has also said that Gaddafi's days are numbered. At a public forum in Washington, held jointly with Secretary of State Hillary Clinton to discuss Libya, Syria and other Middle East issues and reported by the ABC, he said:

Considering how difficult this situation has been the fact is the combination of NATO forces there, the combination of what the opposition is doing, the sanctions, the international pressure, the work of the Arab League — all of that has been very helpful in moving this in the right direction and I think the sense is that Gaddafi's days are numbered.

NATO, meanwhile, has condemned the regime's launch of a SCUD missile fired from Sirte toward rebel-held Brega as "desperate." 

Canadian colonel Roland Lavoie told a news conference that although the unguided ballistic missile killed no one, it had posed "a direct threat to innocent people," Gulf News reports.

Libya has about 240 SCUD missiles in its arsenal, according to the Jane's Defense military journal.

Lavoie labeled the SCUD "a weapon of terror," but said its use in this instance was comparable to "throwing dishes against a wall: it makes a lot of noise, but that's all." 

Libya's rebels have reported moving toward Al-Heisha, a western town that links the capital and Sirte — Gaddafi's hometown and a stronghold for his military, Al Jazeera reports.

"The scouting teams of the revolutionaries reached the outskirts of Al-Heisha after expelling Gaddafi forces," the rebel military command said in a statement early on Wednesday.

Along with Al-Heisha, about 40 miles south of Misurata and 150 miles from Tripoli, the rebels claim to have seized a number of other strategic towns near Tripoli over the past two days, in a series of rebel pushes to isolate the capital.

Rebels say they now hold Zawiya and two other towns on key supply roads to the capital — Gharyan and Surman.

The rebels say they've suffered significant casualties, however: On Sunday, as they advanced on Zawiya, they were targeted in a NATO "friendly fire" air strike and lost a tank and four fighters, the Tripoli Post reports.

Gaddafi forces have also been shelling Zawiya, wounding civilians, Al Jazeera reports. Funerals were held this week for 23 people who rebels said were killed in the government offensive.