28 March 2011 Last updated at 02:32 ET
Coalition air raids have hit Muammar Gaddafi’s birthplace of Sirte, a key target for westward-advancing rebels.
A Libyan government spokesman said three Libyan civilians had been killed in the city’s port.
Unconfirmed rumours that rebels had taken Sirte sparked celebratory gunfire overnight in their stronghold Benghazi.
They came as Nato took full command of the whole military operation in Libya, intended to enforce a UN resolution to protect civilians.
Foreign correspondents in Sirte said they heard several loud explosions in the city as aircraft flew overhead.
A rebel spokesman in Benghazi said Sirte was now in the hands of rebel forces – but there has been no independent confirmation of the claim, and international journalists inside the city suggested it was still in government hands on Monday morning.
Libyan government spokesman Moussa Ibrahim said three young Libyan men had been killed in an air strike on a nearby fishing harbour, but that there was “nothing military or quasi-military” there.
There is no way to independently verify rebel claims they have taken Sirte because their advance is moving at such amazing speed – Sirte is seven hours’ drive along the coastal road from Benghazi. But in the rebel stronghold last night the rumours were enough for the night skies to reverberate for hours with the sound of celebratory gunfire.
The rebels believe the fall of Sirte followed a now-familiar pattern: powerful allied air attacks followed by a rapid rebel advance .
If Col Gaddafi has lost his birthplace, that would be an enormous blow to his attempts to cling to power.
Very little sign has been seen of pro-Gaddafi forces apart from burned-out trucks alongside the coastal road. Most people believe that if they were going to turn and fight they would have done it in Sirte and that they didn’t is hugely significant.
The rebels are starting to believe that Gaddafi’s forces have been demoralised or destroyed to the extent that they can no longer offer significant resistance.
Advance on Tripoli
Heavy explosions were also heard in the capital, Tripoli, late on Sunday. Libyan officials say more than a week of strikes have killed nearly 100 civilians but this cannot be independently confirmed.
The air strikes, intended to prevent Col Gaddafi’s forces from attacking civilian targets among the uprising against his rule, have allowed rebel forces to push westwards at a rapid speed along the coastal highway from their eastern stronghold of Benghazi.
In the last two days a number of coastal communities and important oil installations, including Ras Lanuf, Brega, Uqayla and Bin Jawad, have fallen to the rebels since they took control of Ajdabiya.
Sirte lies about halfway along the coast between Tripoli and and Benghazi.
Journalists in the city on Sunday said it was swarming with soldiers.
“We want to go to Sirte today,” rebel fighter Marjai Agouri told Reuters news agency.
In facts: Sirte
- Birthplace of Libyan leader Muammar Gaddafi
- Port city 450km (280 miles) east of Libya’s capital Tripoli
- Halfway along Libya’s northern coast between Tripoli and rebel stronghold of Benghazi
- Home to some ministerial offices as Col Gaddafi tried to transfer more authority
- Population of around 140,000
“I don’t know if it will happen,” he said outside Bin Jawad with about 100 other rebels armed with rocket launchers, anti-aircraft guns and pickup trucks mounted with machine guns.
On Sunday, Nato’s Secretary General, Anders Fogh Rasmussen, said the bloc was taking charge of the whole military operation in Libya “with immediate effect”.
Mr Rasmussen said Nato’s goal was to “protect civilians and civilian-populated areas under threat of attack from the Gaddafi regime”.
“Nato will implement all aspects of the UN Resolution. Nothing more, nothing less,” he added.
“We are already enforcing the arms embargo and the no-fly zone, and with today’s decision we are going beyond.
“We will be acting in close co-ordination with our international and regional partners to protect the people of Libya.”
The BBC’s Chris Morris in Brussels says the mission to protect civilians was more sensitive because it involved debate about what exactly were legitimate military targets on the ground.
There were disagreements notably between France and Turkey about political control of the mission, but they have now been resolved, our correspondent says.
But the precise rules of engagement have not been revealed, he adds.
Alongside the Nato command structure will be a separate, high-level committee of representatives of all countries taking part in the military action, including Arab states. It will give what one official called “broad political guidance.”
Meanwhile, the battle for Misrata, the last significant rebel-held city in western Libya, has continued.
On Sunday evening, a resident told the BBC that eight people had been killed and 26 wounded – five of them critically – as Col Gaddafi’s forces advanced on the al-Jazeera residential area in the west of the city.
Libyan state TV earlier said Misrata was “secure” and life was “going back to normal”. Security forces had arrested “terrorist gangs”, it said.