SIRTE, Libya — Libya's revolutionary forces seized a convention center Sunday that had served as a key base for fighters loyal to Moammar Gadhafi in the fugitive leader's hometown, as they squeezed remaining regime loyalists in the besieged coastal city.
The inability to take Sirte, the most important remaining stronghold of Gadhafi supporters, more than six weeks after anti-Gadhafi fighters seized the capital has stalled efforts by Libya's new leaders to set a timeline for elections and move forward with a transition to democracy.
Gadhafi supporters also hold the inland enclave of Bani Walid, where revolutionary forces also reported key gains after weeks of faltering advances that resulted in part from the challenging terrain of desert hills and steep valleys. Bani Walid is believed to be harboring high-level figures in the old regime.
The transitional leadership has said it will declare liberation after Sirte's capture because that will mean it holds all of the seaports and harbors in the oil-rich Mediterranean coastal country.
Libya's de facto leader, Mustafa Abdul-Jalil, head of the governing National Transitional Council, said Sunday that anti-Gadhafi fighters have made huge gains in Sirte and Bani Walid, southeast of the capital.
"I do believe, God willing, that the liberation of these cities will happen within this week," Abdul-Jalil told reporters in Tripoli.
He said that revolutionary forces in Sirte have punched their way into the city center in fierce fighting and are now cleaning out pockets of resistance.
In Bani Walid, advancing fighters drove Gadhafi forces out of the airport, said Abdullah Kenshil, who led failed talks for the revolutionaries in search of a peaceful surrender of the city.
"The takeover of Bani Walid is imminent," he said. "The fighters are only one kilometer from the heart of Bani Walid."
He claimed that Gadhafi's son Seif al-Islam was seen on Saturday distributing cash to his loyalists in Bani Walid. "We are 100 percent sure that he is inside, at least until last night," Kenshil said.
Located 250 miles (400 kilometers) southeast of Tripoli, Sirte is key to the physical unity of the nation of some 6 million people, since it lies roughly in the center of the coastal plain where most Libyans live, blocking the easiest routes between east and west.
After a three-week siege from the outskirts, revolutionary forces launched an all-out assault on Sirte on Friday, pounding the city with tank shells, field cannons, rockets and heavy machine guns. Loyalists have put up fierce resistance, and fired back with sniper rifles, mortars and rocket-propelled grenades.
On Sunday, the Ouagadougou Convention Center, an ornate complex that Gadhafi frequently used for international summits, lay in ruins. Throughout the siege, Gadhafi fighters used the walled complex as a base and stronghold. From there they were able to dominate surrounding neighborhoods and assault revolutionaries trying to enter Sirte.
At the nearby Ibn Sina Hospital, scores of wounded civilians crowded the corridors, lying on gurneys and floors to protect them from the shelling and gunfire. There was no electricity or water, and a handful of medical students and nurses were the only medical staff.
Revolutionary fighters roamed the hallways checking IDs and detained about 25 people suspected of being Gadhafi fighters or mercenaries.
"These are all Gadhafi people. They are snipers and we have captured them," said Ahmed Rahman, a field commander, as his soldiers cuffed a suspected pro-Gadhafi sniper.
The revolutionary forces also now control the University of Sirte on the southern outskirts. As they push forward, Gadhafi loyalists are fighting in an ever-shrinking defensive perimeter consisting only of a Gadhafi palace complex, some residential buildings and a hotel near Green Square in the city center.
Associated Press writer Kim Gamel in Tripoli, Libya, contributed to this report.