Forces loyal to Muammar Gaddafi are resisting an advance by Libyan rebels towards the embattled Libyan leader's hometown of Sirte in the fiercest clashes since the start of a sweeping offensive that has brought a string of coastal towns under opposition control.
The rebels, backed by international coalition air strikes, have advanced largely unchecked since Friday but claims in Benghazi, the rebel's eastern stronghold, early on Monday that Sirte had also fallen were premature.
Opposition fighters were engaged in clashes about 100km east of the city, with pro-Gaddafi forces shelling their front lines.
Fighting is ongoing at Nawfaliya, about 180km east of Sirte, where opposition forces say they have come upon a heavily mined road. Pro-Gaddafi forces have dug into positions near the front line, and are shelling opposition fighters.
Al Jazeera's Hoda Abdel Hamid, reporting from the east of Nawfaliya, said: "They [rebels] managed to get really close to Sirte but they didn't get in."
"Sirte will not be easy to take," said General Hamdi Hassi, an opposition commander from the city of Bin Jawad. "Now, because of NATO strikes on [the government's] heavy weapons, we're almost fighting with the same weapons."
Fawzi Bukatif, the commander of the Martyr's Brigade, part of the forces battling Gaddafi, told Al Jazeera: "We're manoeuvring ... we are starting ... we are checking what kind of forces they have there but we are standing at Hagela now - almost 100km from Sirte."
Bukatif said the rebels' progress has been hampered by a lack of weapons as they rely on "old Russian weapons".
"The ... problem we have is we have run out of weapons," he said.
"You know our weapons are traditional ones; the old ones; the Russian weapons. We need ammunition. We need new weapons. We need anti-tanks; we do not have facilities [but] we have the soldiers left behind by Gaddafi ...
"If we do have weapons and ammunitions that we need at the moment, we can move strongly and faster."
There were reports of fresh air strikes by coalition warplanes to the west of Tripoli late on Monday. A French military spokesman also said that French jets had hit a government military command center south of the capital, Tripoli.
British Tornado aircraft also attacked and destroyed Libyan government ammunition bunkers in the Sabha area of the southern desert, the British defence ministry said.
Fresh fighting continued in rebel-held Misurata, where rebels admitted that Gaddafi forces had gained control of part of the town after days of heavy fighting and despite air strikes by French and British forces.
"Part of the city is under rebel control and the other part is under the control of forces loyal to Gaddafi," a spokesman told the Reuters news agency.
Rebels dimissed reports that a ceasefire had been declared by the Libyan foreign ministry in Misurata and that anti-terrorism units there had stopped firing at rebel forces.
Saddun al-Misrati, a member of the rebels' revolutionary committee, told Al Jazeera: "We rubbish this announcement ... Nothing that they say will make a difference on the ground."
Nine people were killed overnight by snipers and shelling by pro-Gaddafi forces, according to a doctor in Misurata, while a resident told Reuters that 24 people had been wounded in mortar attacks by government forces.
A Libyan government spokesman claimed Misurata had been liberated.
Al Jazeera's James Bays has been following the rebel offensive, which has seen them claim the towns of Ajdabiya, Brega, Ras Lanuf and Bin Jawad.
Speaking from Bin Jawad, Bays said it was uncertain where the frontline was. People coming along the coastal road from Sirte said Gaddafi forces were gathered around 60km outside the city, positioned in trees, our correspondent said.
The speed of the rebel advance has stretched lines of communications and created logistical problems, said Bays. One problem is a lack of electricity, which means that petrol pumps do not work.
"At petrol stations they're using plastic bottles on strings down into the tank below the station to pull up fuel," said Bays.
The rebels' advance along the coast has triggered exuberant celebrations in towns along the route such as Ajdabiya with rebel fighters firing their weapons in celebration.
But government forces appear to have been withdrawing their heavy armour, rather than engaging with the rebels.
There were reports on Sunday of a column of military vehicles, including truck-mounted anti-aircraft guns, seen leaving Sirte in the direction of Tripoli, accompanied by dozens of civilian cars carrying families, according to a Reuters reporter in the vicinity.
The opposition's National Council has said it expects a major battle to occur in the area around Tripoli, as opposed to at Sirte.
Gaddafi 'to face trial in Libya'
Meanwhile, Mustafa Abdel Jalil, the head of the opposition national council in Benghazi, claimed Monday that Gaddafi would stand trial in Libya "after the victory" by rebel forces.
"We will try to build a free, democratic country that respects human rights and political alternation," Jalil told France 2 television.
France and Britain also called on Gaddafi to "go immediately" and urged his supporters to drop him before it's "too late" ahead of a London conference starting Tuesday to discuss the crisis in Libya.
David Cameron, the British prime minister, and Nicolas Sarkozy, the French president, also urged Libya's opposition to prepare for a "national political dialogue" leading to free and fair elections.
Barack Obama, the US president who has faced domestic criticism over US involvement in Libya, was due to set out his case for Washington's continuing involvement in international operations in an address on Monday night.
Obama is expected to emphasize that although the US has led the military offensive against Gaddafi, NATO is in the midst of taking command of the operation -- both enforcement of the no-fly zone over Libyan airspace and ground attacks.
NATO on Sunday assumed full command of coalition air operations in Libya.
NATO's secretary-general tells Al Jazeera
that the alliance is "impartial"
Speaking to Al Jazeera, Anders Fogh Rasmussen, NATO's secretary general, said the military alliance was "impartial" and not picking sides, and that its mandate was only to prevent violence against civilians.
Rasmussen said that NATO's taking authority over the military intervention would provide "unity of command".
He also confirmed that several non-NATO countries would be contributing to the military effort, but said he would leave announcements up to individual governments.
James Spencer, a Middle East and North Africa defence analyst, told Al Jazeera that removing Gaddafi from power was "not within NATO's purview".
"If you listen very carefully, the Secretary-General of NATO has been very clear. [Intervention] is to protect civilians against Gaddafi attacks," he said.
But international intervention in Libya was criticised on Monday by Sergei Lavrov, Russia's foreign minister.
"We think that intervention by the coalition in what is essentially a civil war has not been sanctioned by the U.N. Security Council resolution," said Lavrov.