|The opposition remains defiant, saying it would not negotiate with Gaddafi to end the violence [Al Jazeera]
Loud explosions have rocked the Libyan capital, Tripoli, for a third night as forces loyal to Muammar Gaddafi attempt to stop any new attack from an international military coalition enforcing a no-fly zone over the country.
Gunfire and anti-aircraft fire lit up the sky late on Monday in and around the capital, where two large explosions could be heard about 10 minutes apart shortly after 9pm, said Al Jazeera's Anita McNaught, reporting from Tripoli.
She said two naval installations just outside the city, thought to include Abu Sitr Naval Base, had reportedly been hit in the strikes.
"We could see an area of the port on fire, substantially on fire, two big blazes. We saw fire engines racing along the coastal road," she said.
"This evening seems to have been about targeting seaborne military assets of Gaddafi's army, but also we are given to understand [there was] an attack on the airport at Sirte."
Mussa Ibrahim, a government spokesman, told a news conference that the coalition bombardment had killed civilians in port areas and at Sirte airport and had hit the southern town of Sebha, a bastion of Gaddafi's tribe.
"We expect at some point if the casualties are as significant as the Libyans are assuring us they are, there will be some opportunity to verify that for ourselves," McNaught said.
Meanwhile, international coalition forces reportedly struck radar installations at two air defence bases belonging to Gaddafi's forces in Benghazi in eastern Libya.
The developments came as the UN Security Council rejected a Libyan request for an emergency meeting to halt what it called "military aggression" by coalition forces three days after they began launching strikes aimed at disabling Libyan air defences.
The council decided instead to hold a briefing already planned for Thursday to give a briefing on the coalition air campaign to UN secretary-general Ban Ki-moon.
Despite the air strikes, forces loyal to Gaddafi continue to fight on and have reportedly made gains in the west.
Libyan government spokesman Ibrahim said Misurata, Libya's third-largest city 211km east of Tripoli, was "liberated three days ago" and that Gaddafi's forces were hunting "terrorist elements".
But a spokesman for opposition fighters in the city told the AFP news agency that the opposition remained in control despite an onslaught by Gaddafi loyalists, who he said opened fire with tanks and set snipers on roofs to gun down people in the streets.
"Casualties fell in their dozens," after snipers and a tank "fired on demonstrators", the spokesman said.
A medic in Misurata said 40 people had died and at least 300 had been wounded.
The opposition spokesman said Gaddafi's troops "have taken up position along the main road where they have deployed three tanks, as well as positioning snipers on rooftops".
Western town bombarded
Gaddafi forces also reportedly bombarded the western town of Zintan, in the Nafusa Mountain range, for several hours before noon.
"Several houses have been destroyed and a mosque minaret was also brought down," Abdulrahmane Daw told the Reuters news agency by phone from the town.
"New forces were sent today to besiege the city. There are now at least 40 tanks at the foothills of the mountains near Zintan."
There was also fierce fighting further east in Ajdabiya. Opposition fighters were seen retreating in the face of an attack by government forces.
Al Jazeera's Tony Birtley, reporting from an area close to Ajdabiya, said there had been clashes outside the city.
"There's been heavy fighting and heavy shelling going on ... the rebels told me there have been heavy casualties and there are a number of corpses between here and the town [of Ajdabiya] that they have been unable to reach."
He said the road between the eastern city of Benghazi and Ajdabiya was littered with the "burned-out wreckage of what was Gaddafi's armour and tanks," destroyed in air raids by coalition forces.
Government troops retreated 100km from Benghazi, the opposition stronghold, after fierce strafing by coalition aircraft destroyed much of their armour, AFP reported.