SIRTE, Libya -- Libyan revolutionary forces fought building by building Wednesday against the final pocket of resistance in Muammar Qaddafi's hometown -- the last major city in Libya to have been under the control of forces loyal to the fugitive leader.

While Libya's transitional leadership worked to consolidate control over the entire country, the country's acting prime minister warned in a newspaper interview that Qaddafi can still cause trouble from his hiding place.

Mahmoud Jibril was quoted by the pan-Arab Asharq Al-Awsat paper Tuesday as saying that the ousted leader is moving between Niger, Algeria and the vast southern Libyan desert and has been trying to recruit fighters from Sudan to help him establish a separate state in the south, or to march to the north and destabilize the new regime.

The report could not be confirmed, but it underscored fears that the inability to catch Qaddafi, who escaped with two of his sons after revolutionary forces swept into Tripoli in late August, would allow him and his supporters to wage an insurgency.

"Qaddafi has two options: either to destabilize any new regime in Libya or to declare a separate state in the south," Jibril was quoted as saying, adding there was evidence about this but he didn't elaborate.

Suggesting that the U.S. also was concerned about the possibility, Secretary of State Hillary Rodham Clinton said during a visit to Tripoli Tuesday that she hoped Qaddafi would be captured or killed.

Although two months have passed since Qaddafi fled the capital, Libya's new leaders have refrained from declaring national "liberation" until the fall of Sirte, which Qaddafi transformed from a fishing village into a modern city after he seized power in 1969.

Revolutionary forces on Tuesday pushed from the east into the small pocket of the city under the control of Qaddafi loyalists and captured a vegetable market, though they came under heavy fire from snipers and rocket-propelled grenades on the rooftops of residential buildings and homes along major streets.

On Wednesday, Wissam bin Hmade, the commander of one of the revolutionary brigades from the eastern city of Benghazi, said they had the Qaddafi supporters corralled in a 700 square meter residential area but were still facing heavy rocket and gunfire from snipers holed up in surrounding buildings.

It took the anti-Qaddafi fighters, who also faced disorganization in their own ranks, two days to capture a single residential building.

Another commander, Khaled al-Maghrabi, said 15 fighters were killed in a friendly fire incident.

It is unclear whether loyalists who slipped out of the besieged cities of Bani Walid, which was captured this week, and Sirte might continue the fight and attempt to organize an insurgency using the vast amount of weapons Qaddafi was believed to have stored in hideouts in the remote southern desert.

Unlike Iraq's Saddam Hussein, Qaddafi had no well-organized political party that could form the basis of an insurgent leadership. However, regional and ethnic differences have already appeared among the ranks of the revolutionaries, possibly laying the foundation for civil strife.

Qaddafi has issued several audio recordings trying to rally supporters. Libyan officials have said they believe he's hiding somewhere in the vast southwestern desert near the borders with Niger and Algeria.

The whereabouts of two of his sons also remain unknown, although commanders have said they believe Muatassim and Seif al-Islam are hiding in Sirte and Bani Walid, respectively. Seif al-Islam had been Qaddafi's likely choice to succeed him as Libya's leader.

Anti-Qaddafi fighters combed Bani Walid on Tuesday for signs of Seif al-Islam and other high-level regime figures in the desert enclave, 90 miles southeast of Tripoli.

"Seif was seen on Thursday. He was eating in a desert village close to the city," one field commander, Said Younis, said.

The Netherlands-based International Criminal Court has charged Seif al-Islam, his father and Qaddafi's former intelligence chief Abdullah al-Senoussi with crimes against humanity for a brutal crackdown on the uprising.