Reports say Libyan rebels have entered the northwestern town of Yafran, previously held by government forces, as the NATO chief says he is confident that people across Libya can start preparing for a future without Muammar Gaddafi, the country's long-time leader.
Youssef Boudlal, a Reuters photographer in Yafran, on Monday said the town had been wrested by the rebels.
"We are inside the town ... There is no sign of any Gaddafi forces. I can see the rebel flags ... We have seen posters and photos of Gaddafi that have been destroyed," Boudlal said.
Al Jazeera's Cal Perry, reporting from the rebel stronghold of Benghazi in eastern Libya, said it was not clear what tilted the balance in the rebels' favour in Yafran.
"We do not have details of what provided this breakthrough ... this is a town that has been held by Gaddafi forces since the start of the fighting," he said.
"But what we saw this morning was rebels rolling into a town just 100 miles from the capital, really on the doorstep of Gaddafi.
"What propelled this to happen, we still don't know. But what we do know is that the clock certainly seems to be ticking on Gaddafi. This is really the first challenge to the city of Tripoli that we have seen in about four months."
The rebel advance came amid intense fighting between forces loyal to Gaddafi and rebels seeking to end his more than four-decade-long rule.
It also came as Anders Fogh Rasmussen, NATO's secretary-general, said damaging or destroying of 1,800 military targets so far in Libya had degraded Gaddafi's power to the extent that he would certainly be forced from power.
"We have made considerable progress," he said before a meeting of NATO defence ministers due to take place in Brussels.
"We have taken the momentum, we have turned the tide of terror unleashed by the Gaddafi regime, we have saved countless lives and we have seriously degraded the ability of the Gaddafi regime to attack civilians."
Reuters news agency reported that loud explosions shook Tripoli on Monday night in what appeared to be stepped up NATO air strikes on the Libyan capital. Explosions were heard in the city just before midnight, the latest in several rounds of bombings in the last two days.
Libyan TV said al-Karama neighbourhood was hit by NATO forces, which have been bombing targets of Gaddafi's government since March.
It said a telecommunications station was hit in a bombing.
Rasmussen said about 100 command-and-control centres had been successfully targeted, on top of more than 700 ammunition stores and almost 500 tanks, armoured personnel carriers and rocket launchers.
Signalling that he will ask allies to increase their participation, he said: "I will request a broad support for our operation in Libya ... I think that for the sustainability of our operation it is essential to ensure a support for our operation that is as broad as possible."
Opposition rebels have been buoyed by NATO air raids attacking Gaddafi forces. The military alliance has deployed attack helicopters for precision attacks, boosting rebels further.
Over the weekend, powerful explosions were heard in the Libyan capital, Tripoli, as NATO fighter jets launched intensive air raids on the capital and its eastern suburbs.
The Tripoli explosions came as William Hague, the British foreign secretary, said there was no deadline for NATO's Libya operation, and Russia voiced concerns that the use of helicopters showed NATO was sliding towards a land campaign.
"We're not going to set a deadline," Hague told an interviewer on BBC television on Sunday.
Hague, who held talks with Libyan rebel leaders in Benghazi on Saturday, ruled out putting ground forces, saying NATO would stick to the terms of a UN Security Council resolution passed in March to protect civilians.
"We will continue in that way, intensifiying what we're doing - the Apache helicopters are an example of that - but that's different from mission creep," he said.
Hague's trip came just hours after British Apache helicopters attacked forces loyal to Gaddafi.
"We're encouraging the National Transitional Council to put more flesh on their proposed transition - to lay out in more detail this coming week what would happen on the day that Gaddafi went - who would be running what, how would a new government be formed in Tripoli?" he told the BBC.
Hague earlier said Britain would support demining efforts in Misurata, the main rebel-held city in western Libya, and deliver "more equipment, uniforms, bullet-proof jackets" to rebel fighters.
"We have no combat troops in Libya," he said. But Britain, he said, would stand with the Libyan people "for as long as it takes".
Earlier, Russia, which is calling for a negotiated solution to the Libyan conflict, expressed alarm over the use of helicopters by NATO, with Sergei Lavrov, the foreign minister, saying that the decision was "deplorable".
"We consider that what is going on is either consciously or unconsciously sliding towards a land operation," he said on Saturday.
NATO attacks on the Libyan military and government infrastructure have been occurring daily since March 31 in an operation that has just been extended for another 90 days.
The 18-country mission, led by the US, UK and France, has several core goals: enforcement of a no-fly zone, maintenance of an arms embargo, protection of civilians and facilitation of humanitarian assistance.