Libyan rebels plan siege on Tripoli?

LONDON, April 14 (UPI) -- Anti-Gadhafi rebels are preparing an assault on Tripoli to encourage residents to stand up to the Libyan dictator, sources in the transitional council said.

A "loud explosion" was reported near a Gadhafi compound in Tripoli and NATO jets were reportedly circling over the capital city, Britain's The Guardian newspaper reports.

The U.N. Security Council in March passed a resolution sanctioning military intervention in Libya to protect civilians from attacks by pro-Gadhafi forces.

Sources in the rebel-backed transitional council told London's pan-Arab daily Asharq al-Awsat anti-Gadhafi forces were preparing for an operation in Tripoli.

Plans, the source said, are said to target the Bab al-Aziziyah military complex in Tripoli.

"Gadhafi must take this threat seriously, this is not an empty threat," rebel sources said. "We are marching on him."

The same source told the London daily on condition of anonymity Gadhafi's time is running in out Libya.

The so-called Libyan Contact Group during a meeting in Doha this week said Gadhafi's presence undermines any chance for peace.

It said "Gadhafi's continued presence would threaten any resolution of the crisis" and "called on all Libyans who wanted to see a process of political transition to urge Gadhafi to step down."