Nato warplanes launched air strikes on Libyan capital Tripoli today, state television reported, and a government spokesman said three people were killed.
Nato initially said the only air strike it could confirm took place this afternoon and targeted a surface-to-air missile battery 40km south of Tripoli. It dismissed the report of civilian casualties as "misinformation".
But a Nato official later said mission reports indicated Nato pilots had hit two more targets closer to the city centre.
Earlier today, a Reuters witness said Libyan government forces fired anti-aircraft guns at Nato warplanes from positions in central Tripoli.
Elsewhere, Government forces heavily shelled the port area in Misrata today, forcing its closure, a rebel spokesman said.
"The port area was heavily shelled today and the destruction there is huge. I was there and saw for myself," the spokesman said.
"Over 200 Grad missiles fell on the port area, including residential neighbourhoods near the port. They shelled this area because the port is Misrata's only window to the outside world. The port was shut today because of the shelling."
Libyan rebels have warned of an impending "massacre" in Misrata as troops loyal to Muammar Gadafy intensified their assault on the coastal city.
As shelling continued in the city centre today, US secretary of state Hillary Clinton urged Nato to maintain unity, saying Colonel Gadafy was trying to test the alliance's resolve in the Western-led air campaign against his forces.
"As our mission continues, maintaining our resolve and unity only grows more important," Ms Clinton said to a Nato foreign ministers' meeting in Berlin amid signs of strain within the alliance. "Gadafy is testing our determination."
She spokes as rebels warned that if Nato did not step up its attacks on government forces there would be heavy civilian casualties in Misrata. "A massacre . . . will take place here if Nato does not intervene strongly," a rebel spokesman said.
At the meeting in Berlin, Ms Clinton said the international coalition was "escalating the pressure and deepening the isolation of the Gadafy regime" and called for efforts to "sharpen the choices" facing those around him.
Ms Clinton reaffirmed the US commitment to the military campaign against Col Gadafy but stopped short of signalling a stronger US role after Washington relinquished command of the operation to Nato last month.
UN secretary general Ban Ki-moon, EU foreign policy chief Catherine Ashton, Arab League head Amr Moussa and officials from the African Union and Organisation of the Islamic Conference were also due to discuss Libya at Arab League headquarters in Cairo today.
Foreign ministers from a group of Western powers and Middle Eastern states met yesterday in Qatar and jointly called for the first time for an end to Col Gadafy's 41-year rule.
Britain and France are leading air strikes against Col Gadafy's forces, but have grown frustrated with the lack of support from Nato allies. After heading up the campaign in its early days, Washington is taking a back seat, and other Nato states are playing smaller roles.
"Gadafy and his regime has lost all legitimacy and he must leave power allowing the Libyan people to determine their future," the "contact group" of Western and Middle Eastern states meeting in Qatar said in a final statement yesterday.
It also said the rebels' national council, "in contrast with the current regime ... is a legitimate interlocutor, representing the aspirations of the Libyan people".
The United States is receptive to concerns of its allies but believes Nato is doing a good job in Libya and that the US military will continue to play a supporting role, State Department spokesman Mark Toner said.
Reuters