Libya's new rulers have insisted Sirte's fall is imminent, and they expect to declare liberation this week. That could allow them to name a new interim government and set a timeline for holding elections within eight months.
But Gadhafi's forces have proven resilient, fighting back fiercely despite heavy shelling and NATO airstrikes.
Former rebels control much of the battered coastal city after launching a major push a week ago, but they were still under intense sniper fire Friday. Wounded fighters streamed into front line medical units, then were evacuated to field hospitals on the city's outskirts.
Pro-Gadhafi forces also maintain control over the desert town of Bani Walid.
NATO was conducting "intensive overwatch missions" around both areas, according to the British Ministry of Defense.
British warplanes struck three armed trucks belonging to former regime forces hidden beneath trees east of Bani Walid on Thursday, the ministry said.
"The vehicles were successfully engaged by our aircraft, using Paveway guided bombs, and destroyed," Maj. Gen. Nick Pope said in a statement.
NATO has called the continued resistance by Gadhafi forces in Sirte "surprising," as they appear to be losing the battle since revolutionary forces have the area surrounded.
Tanks and weapons-mounted vehicles from the revolutionary forces have kept up a steady barrage of fire into the small enclave known as District 2, where commanders believe several hundred remaining loyalists, possibly including high-ranking figures from the former regime, are hiding.
Thousands of civilians have fled the city to escape the violence.
One resident returned Friday to collect personal items from his home, which had been used as a firing position for pro-Gadhafi forces. Their uniforms littered the front courtyard.
The owner, who would not give his name because of fear of reprisals, left carrying just a blanket, saying, "the pictures speak for themselves." He then left the city with several of his relatives.
