Libyan provisional government forces backed by NATO warplanes raced through the eastern outskirts of Sirte on Monday, closing in on Moammar Gadhafi loyalists holed up in one of the last two bastions of the deposed leader.
Thick, black smoke billowed into the air as National Transitional Council (NTC) fighters battled loyalist troops at a roundabout about a mile from the center of Gadhafi's home town, Reuters journalists said.
The thud of large explosions could be heard as NATO aircraft roared overhead. NTC fighters said the jets were striking the positions of Gadhafi loyalists.
The advance came two days after anti-Gadhafi fighters west of Sirte drove to within a few hundred yards of its center before pulling back on Sunday to make way for NATO strikes.
On the western edges of Sirte on Monday, NTC fighters and Gadhafi loyalists traded heavy machine gun fire, rocket-propelled grenades and artillery rounds.
Snipers loyal to Gadhafi could be seen on building rooftops. NATO aircraft flew overhead.
NATO would not comment on its operations in Sirte on Monday. It said its planes hit eight targets on Sunday, including ammunition stores and rocket launchers.
Interim government forces have previously retreated from Sirte and the other remaining Gadhafi stronghold, Bani Walid, after poorly organized attacks met fierce resistance from loyalists.
Sirte lies between Tripoli and the eastern city of Benghazi, both now held by the NTC whose rebel fighters overran the capital five weeks ago after six months of fighting.
Taking Sirte would be a huge boost for the NTC, which is trying to establish credibility as a government able to unite Libya's fractious tribes and regions, and a blow for Gadhafi, widely believed to be in hiding somewhere in Libya.
Humanitarian organizations have raised the alarm over conditions for civilians cut off in Sirte and in Bani Walid to the south.
"God willing we can enter Sirte by tonight," NTC fighter, Emad al-Amamy, told Reuters on the eastern edge of the city earlier on Monday.
Scores of civilians in cars laden down with personal belongings continued to stream out of the town to both the east and west. NTC fighters checked them, looking for wanted figures among those who were, and may still be, loyal to Gadhafi.
International aid groups are demanding access.
"We are very concerned about the people inside and near Bani Walid and Sirte," Georges Comninos, who heads the International Committee of the Red Cross (ICRC) in Libya, said in a statement.
"Food reserves and medical supplies are reportedly running short in both cities. We are receiving many appeals to help the wounded and come to the aid of civilians generally."
NTC fighters and people who have fled Sirte have alleged that pro-Gadhafi fighters were trying to prevent civilians from getting out of the city, effectively using them as human shields.
"Gadhafi's forces have surrounded the area, closed it off, by shooting at people," said a man called Youssef, driving away from Sirte with his wife. "There are a lot of people who want to get out but can't."
Gadhafi's fugitive spokesman said on Monday that he was in Sirte when it came under attack on Sunday but he refused to comment on the toppled leader's whereabouts.
"I was yesterday in Sirte," Moussa Ibrahim told Reuters in a satellite phone call. "The situation is quite bad."
Ibrahim said Gadhafi was in Libya and "very happy that he is doing his part in this great saga of resistance."
He added that the humanitarian situation in Sirte was dire because the hospital in the city had run out of medical supplies and equipment, and there was a total power outage.
Gadhafi loyalists showed they were still a threat by launching an attack on Sunday on the desert oasis town of Ghadames, on the border with Algeria, NTC officials said.
It underlined the fragility of the NTC's grip even on parts of the country nominally under its control. The town, about 600 km southwest of Tripoli, is near a border crossing that Gadhafi loyalists have used to flee into Algeria. Its old town, an intricate maze of mud walls, is a UNESCO world heritage site.
Military spokesman Ahmed Bani said the town would be under the control of NTC fighters within days.
The NTC also said on Sunday that it had found a mass grave containing bodies of over 1,000 people killed by Gadhafi's security forces in a 1996 massacre of prison inmates in Tripoli.
The mass grave was the first physical evidence found so far of the Abu Salim prison massacre, an event that was widely spoken of in Libya but covered up for years, creating simmering anger that ultimately helped bring about Gaddafi's downfall.
The uprising that toppled Gadhafi was ignited by protests linked to the Abu Salim massacre. In February, families of people killed there demonstrated in Benghazi to demand the release of a lawyer who had been representing them. Against the backdrop of the overthrow of authoritarian rulers in Egypt and Tunisia, the protests gathered pace and won Western backing.
Despite taking the capital in August, the new rulers say they cannot begin the process that would lead to elections until Sirte and Bani Walid fall. Wrangling over ministerial portfolios has prevented them from forming a caretaker government.