Columns of Libyan government forces pushed deeper into the heart of Muammar Gaddafi's hometown of Sirte on Saturday, fighting resistance that appeared ever weaker.

The advance by forces of the interim government, the National Transitional Council, which at one point came within 500 metres of the city's main road, was slowed by snipers in several apartment buildings and a bunker. But in some areas the fighters have made significant progress.

The advance came through an area know as the Seven Hundreds, a district of unfinished houses backed by a sprawling suburb that only fell to government forces during fierce fighting on Friday that continued late into the night. Yesterday it was a ghost town, the streets littered with empty shell casings and smashed cars. The area is next to a compound belonging to the former dictator and includes a military base which yesterday was under control of NTC fighters.

On Friday a bulldozer was widening a sandy road leading to a breach in the wall encircling the neighbourhood which defenders had used as a firing position for weeks. Deserted villas showed signs of the heavy fighting, with holes made by shells and RPGs in the walls of many houses.

The solitary resident was a man of 75 who insisted he had been fed and treated well by revolutionary fighters who had found him. He was the only civilian encountered in Sirte by the Observer all day.

Since Friday revolutionary forces have pushed Gaddafi loyalists back several kilometres from defensive positions outside Sirte and are contesting control of the centre of the city in often-chaotic street-by-street battles.

As gun trucks sped ahead, fighters ran to keep up with them, halting only to fire at buildings containing snipers before being stopped at a crossroads. The fighters said they had the impression that the defenders were running low on ammunition, firing few rockets and avoiding prolonged firefights. Two fighters were killed early in the fighting, but firing on the column was sporadic.

Revolutionary forces launched a major attack on Friday, pushing into the coastal city from the west, east and south after a three-week siege from the outskirts in which they said they were giving civilians time to flee.

Suleiman Ali, commander for revolutionary forces, said loyalist forces have been driven from Ibn Sina Hospital where hundreds of civilians have sought refuge from the fighting.

"They're fighting us fiercely because, for sure, Mo'tassim [one of Gaddafi's fugitive sons] is inside Sirte," said Abdulrazaq Haroun, one of the NTC commanders.

Taking Sirte would bring Libya's new rulers closer to establishing control of the entire country almost two months after they seized the capital Tripoli, but they are also under pressure to spare the civilians trapped inside. Before the latest assault on the city more civilians took the opportunity to flee, queuing to be searched at checkpoints.

Thousands have fled Sirte, describing increasingly desperate conditions for those remaining. "We could not understand who was firing," said Milad Abdul Rahim, who was heading out of Sirte. "It is just random."

Hassan Massoud drove out of the city in a pick-up truck with his family in the cab and luggage teetering on the back. He said he decided to leave after his neighbour's house was hit: "It was single-storey. It collapsed on them. It killed a man and a girl," he told Reuters.

The NTC believes Gaddafi is not in Sirte but far south in the Sahara desert.