Tripoli/Washington, Aug 22 (IANS) Libyan rebels Monday tightened their grip on Tripoli with the capture of three of Muammar Gaddafi's sons and a hunt was on for the 68-year-old Libyan leader.


Rebel commanders say they have taken control of about 80 percent of the city following an overnight assault on the capital, BBC reported.

Fighting was still raging Monday evening around Gaddafi's compound in Tripoli but the whereabouts of the Libyan leader, who ruled the oil-rich country for over 40 years after seizing power in a bloodless coup in 1969, were still unknown.

World leaders have urged Gaddafi to step down, and Egypt has recognised the rebels as the legitimate government.

With three of the Libyan leader's sons in their custody, rebel forces were battling Gaddafi forces on his home turf, CNN reported.

Libyans seeking Gaddafi's ouster rejoiced Sunday after news that two of the ruler's sons -- Saif al-Islam and Saadi -- had been arrested by opposition forces.

On Monday, a third Gaddafi son, Mohammed, was also taken into custody, the broadcaster said.

Rebel troops were seen waving opposition flag in Tripoli's Green Square, where most of the government offices are located. They faced stiff resistance close to the Libyan leader's compound.

Government tanks Monday rolled out of Gaddafi's Bab al-Aziziyah compound in a bid to fend off rebels who already controlled most of the capital.

Many streets in the city centre were left empty as they came under sniper shots and artillery fire, the Al Jazeera TV reported.

US President Barack Obama said Sunday that Muammar Gaddafi's rule in the country has come to an end and asked him to relinquish "power once and for all".

"Tonight, the momentum against the Gaddafi regime has reached a tipping point," Obama said in a statement issued by the White House.

"The Gaddafi regime is showing signs of collapsing."

Mustafa Abdul Jalil, who heads the National Transitional Council (NTC), said in an TV interview that Gaddafi's second son Saif al-Islam has been captured and was under custody in a safe place, Xinhua reported.

The International Criminal Court (ICC) prosecutor's office later confirmed that Saif al-Islam has been detained.

The ICC had issued arrest warrants in June for Gaddafi, Saif al-Islam and intelligence chief Abdullah al-Senussi, charged with crimes against humanity.

NTC vice chairman Abdel Hafiz Ghoga said that Libya has entered a new era by overthrowing the Gaddafi regime.

"Tonight is historical," said Ghoga.

He said Gaddafi was still in Libya and that he hoped to arrest him and bring him to trial soon.

Gaddafi in an audio speech broadcast Sunday said all tribes should march to Tripoli to "purify" the city.

"The west will not protect you. Tripoli will be destroyed," he said.

Saying that he was in Tripoli, Gaddafi called on his supporters to defend the capital from the rebels and pledged to "emerge victorious" rather than surrender.

Moussa Ibrahim, spokesman for Gaddafi's government, said around 1,300 people were killed in the fighting in Tripoli since Sunday noon.

He said that 5,000 people were wounded in the battle and the NATO should be held responsible for the bloodshed.

Al Jazeera reported that residents of the city began to stream into streets to welcome the opposition troops, despite Gaddafi's call urging people to take up arms to guard his rule.

Thousands of people also flocked into the streets in rebel-held Benghazi, to celebrate the collapse of Gaddafi's rule.

As the rebels dramatically stormed Tripoli after months of waging a war against the government troops, President Obama said: "Muammar Gaddafi and his regime need to recognize that their rule has come to an end."

The US president also called on the main opposition NTC to "steer the country through a transition by respecting the rights of the people of Libya, avoiding civilian casualties, protecting the institutions of the Libyan state, and pursuing a transition to democracy that is just and inclusive for all of the people of Libya".

Obama vowed that the US will continue to "insist that the basic rights of the Libyan people are respected" and "support the peaceful transition of democracy".