At least 18 people were killed and nearly 300 wounded in two days of clashes as Libya's new regime fighters struggled to take full control of Moamer Kadhafi's hometown of Sirte, medics said on Saturday.
The push by National Transitional Council (NTC) fighters squeezed Kadhafi's diehard loyalists into an ever tighter net in Sirte, correspondents on the ground said.
NTC chief Mustafa Abdel Jalil predicted "the battle for Sirte and Bani Walid will be very vicious," referring to the two holdouts of Libya's fallen leader.
Hassan Umran, in charge of the registry at a field hospital 50 kilometres (30 miles) west of Sirte, said 17 people were killed and 230 wounded in the fighting on Friday alone.
One was killed and 58 wounded on Saturday, he said.
Forces from Libya's interim regime scored a strategic goal on Saturday, seizing a four-lane avenue which opens the way to a final assault on a key base of Kadhafi's troops.
But with thousands of civilians still trapped in the ex-leader's hometown, NTC commanders said they were pacing their advance to evacuate some of those who had not fled and to avoid losses from friendly fire.
Attacking from the east, NTC fighters seized the road to the Ouagadougou conference centre, a key base of pro-Kadhafi fighters still holding out after days of heavy pounding by NTC tank, cannon and rocket fire and ground assaults.
The advancing forces reached within between 500 metres (yards) and one kilometre of the centre and the nearby university, as Kadhafi loyalists responded with sporadic mortar and small arms fire, a correspondent said.
Naji Mismari, an NTC commander, said several Kadhafi loyalists were killed but without giving a number. "Their corpses are still in the houses," he said, adding that 17 trapped families were evacuated.
On the western front, fighting concentrated on the so-called 700-house complex where NTC forces fired RPGs and machineguns while Kadhafi loyalists used snipers and mortars.
"A sniper hit one of my men and the bullet went right through his head, killing him," said fighter Nabil Meftah. "Now the snipers are in the tall buildings further into the city."
After launching on Friday what they called a final assault on Sirte with a barrage of rocket and artillery fire, the NTC forces still faced stiff resistance by late Saturday.
With the NTC awaiting the capture of Sirte to declare the liberation of the whole of Libya, clearing the way to draw up a timetable for elections, its fighters resumed the assault earlier on Saturday after a sandstorm eased.
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Civilians trickled out on foot during a short lull, including a woman who carried a child in her arms and a man lugging suitcases, as NTC forces stopped cars for identity checks and searches.
"We just want to go somewhere that is safe. I hadn't been out of my house for three weeks because of all the firing. Lots of houses in my area were hit," said Sudanese labourer Abdulrahim Kabash.
Earlier, NTC fighters overlooking the Ouagadougou centre said its concrete bunkers were proving tougher than they originally thought.
"It has been hit for days by tank guns and rockets, but it hasn't budged. Its paint has hardly been scratched," said one of them, armed with a Kalashnikov assault rifle.
Late on Friday, NTC interim defence minister Jalal al-Digheily said the end of the conflict was near.
"We are very close to the end of the war and peace will be restored all over Libya," he told reporters in Tripoli on the occasion of visits by the British and Italian defence ministers, Liam Fox and Ignazio La Russa.
"There are still some hot spots but they won't resist very long," he added of Sirte and Bani Walid, a desert oasis 170 kilometres (100 miles) southeast of the Libyan capital.
NATO said on Saturday that one "firing and vehicle staging point was engaged and destroyed in Sirte" on Friday.
British defence minister Liam Fox said in Tripoli said the alliance will keep up its military operations for as long as remnants of Kadhafi's regime present a risk to the people.
"The message for those who are still fighting for Kadhafi is 'the game is over,' that they are rejected by the Libyan people," Fox added.
As the battle for Sirte appeared to be nearing its end, the United Nations urged the NTC, which has ruled most of the oil-rich country since its forces overran Tripoli on August 23, to avoid revenge attacks.
"Libya's revolution is based upon the demand for human rights and dignity," UN chief Ban Ki-moon's special representative, Ian Martin, said in a statement on Friday.
"I appeal to all to respect the calls made by the National Transitional Council that there should be no revenge even against those responsible for war crimes and other grave violations."
Outside Bani Walid, an NTC commander told AFP on Friday that a new mediation attempt was under way with tribes there, but if it failed a fresh assault would be launched.
NTC commanders have said Kadhafi's most prominent son, Seif al-Islam, is in Bani Walid and possibly Kadhafi himself as well.