|This map shows the areas that rebels have taken over and are now struggling to defend against Gaddafi forces
Forces loyal to Muammar Gaddafi, the country's long-time leader, have been staging a fightback against opposition forces, taking the town of Bin Jawad and moving on to the oil port of Ras Lanuf.
Witnesses have also told Al Jazeera that Az Zawiyah, in the west of the country near the capital Tripoli, was under heavy attack by government forces.
There has been fierce fighting in Misurata, located between Tripoli and Gaddafi's hometown Sirte, with reports of at least 18 people killed.
However, Al Jazeera's Jacky Rowland, reporting from the town of Brega, said that the opposition forces had advantages in terms of "their sheer number, patriotism and enthusiam".
"For a few days the rebels were making gains, but overnight it would appear that pro-Gaddafi forces took some ground," our correspondent said.
Government forces appeared to have "drawn a line in the sand" on the road to Sirte, Gaddafi's hometown, she said. "If the rebels want to capture Sirte, they will have to prepare for heavy fighting along the way."
At the hospital in Brega, 42 injured members of the opposition force were being treated, while there were confirmed deaths of at least eight, our correspondent reported.
"The vast majority of those injured had been injured by their own weapons," she said, explaining that the rebels had little or no military training.
"People with no prior military experience, telling the soldiers that they want to fight and they want to fight in the anti-Gaddafi forces."
The opposition forces "have plenty of rifles and ammunition", but Gaddafi's troops had aircraft which the rebels did not, Al Jazeera's Rowland said.
With helicopter gunships, fighter jets and tanks, Gaddafi loyalists have pounded opposition fighters with artillery, rockets and gunfire in several cities, including Bin Jawad, Tobruk, Ras Lanuf and Misurata.
Abdel Basset Abu Zouriq, a spokesperson of the opposition, told Al Jazeera on Monday that Misurata was still under control of opposition forces.
"Pro-Gaddafi forces are still somewhere outside the city, regrouping for future attacks," he said.
Jacky Rowland reports on the fight for Ras Lanuf
He said that the city was anti-Gaddafi in general and so government forces could only attack the city or invade it for few hours and then withdraw.
In the rebel stronghold of Benghazi, much of the euphoria and excitement that victory was close at hand had faded, Al Jazeera's Hoda Abdel-Hamid said.
Some feared that pro-Gaddafi forces had deliberately retreated to around Sirte, drawing the inexperienced and poorly equipped rebel fighters forward and leaving rebel-held towns exposed to a possible counteroffensive.
"Some people told me all the young people had gone to the front. There is no one left to protect the city," our correspondent in Benghazi said.
"There is an understanding that [Gaddafi's ousting] is not going to happen so easily."
Abu Sadr, an opposition activist in Benghazi, told Al Jazeera that for the time being people in the city were very relaxed.
"We know we are safe from any attack on the ground and government forces are not going to come into Benghazi unless it is an air force attack," Sadr said.
"From Brega to Ras Lanuf is important, because Gaddafi forces are very close."
Gaddafi may also be seeking dialogue, with a former prime minister appearing on state television urging opposition members to join talks.
Gaddafi himself made a brief appearance in Tripoli's Green Square on Sunday night, but disappeared almost immediately.
Crowds were seen celebrating and shouting the leader's name as he appeared in Tripoli's Green Square, but no explanation was given as to why state TV did not stay with footage of the president.
They instead cut back to the studio, going on to a separate interview.
He also appeared in an interview for television station France 24, where he repeated claims that al-Qaeda was responsible for plunging the country into chaos.
Gaddafi said that Libya was an important partner to the West in containing al-Qaeda and also played a vital role in keeping sub-Saharan illegal migrants trying to reach Europe.
"Even the Israelis in Gaza, when they moved into the Gaza Strip, they moved in with tanks to fight such extremists," Gaddafi said, likeing the Palestinians to al-Qaeda.
"It’s the same thing here! We have small armed groups who are fighting us. We did not use force from the outset ... Armed units of the Libyan army have had to fight small armed al-Qaeda bands. That is what’s happened."