Pro-Gaddafi forces are mounting a major assault on the rebel stronghold of Benghazi, despite the government’s declaring a ceasefire, Al Jazeera reported.
Tanks and troops entered the rebel-held city on Saturday, and the head of the rebel Libyan National Council says there has been heavy artillery bombardment.
"Now there is a bombardment by artillery and rockets on all districts of Benghazi," Mustafa Abdul Jalil told Al Jazeera.
"There will be a catastrophe if the international community does not implement the resolutions of the UN Security Council," he said.
The Libyan government is denying claims of attacks.
A fighter jet was shot down over the city earlier on Saturday, despite a UN resolution declaring a no-fly zone over Libya. It is however unclear who the jet belonged to.
Leaders from the United States, Britain, France and Arab countries are meeting in Paris later today to discuss ways to act on the resolution authorizing "all necessary measures" to protect civilians.
The French ambassador to the UN, Gerard Araud, said military intervention could begin within hours of Saturday's summit.
U.S. President Barack Obama earlier said Gaddafi must stop the violence or face military action.
On Friday, Gaddafi's government declared a unilateral truce but there were reports that fighting was continuing.
MOSCOW, March 19 (RIA Novosti)
