Thousands of troops loyal to Muammar Gaddafi, the Libyan leader, have advanced on the rebel-held western city of Misurata, shelling it from two sides, in attacks that have reportedly killed at least 12 rebels.
"He has sent thousands of troops from all sides and they are trying to enter the city. They are still outside, though," Hassan al-Misrati, a rebel spokesman, told Reuters on Wednesday from inside the town.
Al Jazeera correspondent Tony Birtley, reporting from Misurata, said Gaddafi troops have shelled the city’s frontline.
"In a two-pronged attack, forces loyal to Gaddafi have attacked in the west as well as east of the city," he said.
"As per reports there has been heavy casualty on the sides of the rebels."
Our correspondent said: "We have also been told that the Gaddafi troops have fired grad rockets and Milan wire-guided missiles.
"There has been non-stop firing and landings of grad rockets throughout the day but no NATO strikes have taken place at the moment."
"Probing attacks are being made by Gaddafi forces in the last couple of days but they have been pushed back."
There was no immediate comment from the Libyan leader's government.
Abdulrahman, a rebel spokesman from Zintan, said that Gaddafi's forces had also shelled the western town on Wednesday morning, after massing large numbers of troops towards it.
"They are now using anti-aircraft weapons," he said.
The offensive followed a drop in NATO bombing of Tripoli on Wednesday, after 24 hours of some of the heaviest bombardments of the Libyan capital since air strikes began in March.
Meanwhile, the Libyan rebels continue to gain diplomatic recognition.
Spain on Wednesday said it had recognised the rebel National Transitional Council [NTC] as the country's only representative.
"I'm here today to confirm that the National Transitional Council is the only legitimate representative of the Libyan people," Trinidad Jimenez, the Spanish foreign minister told reporters in the eastern Libyan city of Benghazi.
Yesterday, Mikhail Margelov, a Russian envoy who also visited Benghazi, said that Gaddafi had lost his legitimacy.
"Russia is ready to help now; Russia is ready to help politically, economically and in other possible ways," Margelov said.
"We are as a prominent member of the National Security Council, we are, as a member of G8, ready to carry our part of responsibility for the future of these extremely important Arab and African nations."
In a break from its earlier stands, China on Friday said it was reaching out for the first time to the Libyan rebel council, with the country's ambassador to Qatar meeting with the head NTC in Doha, the Qatari capital.
NATO vowed on Wednesday to keep up its relentless bombing campaign in Libya until Gaddafi steps down.
"We want to see increased urgency in some quarters in terms of Libya"
Anders Fogh Rasmussen, NATO secretary-general
NATO allies meeting in Brussels pledged to stay in Libya "for as long as necessary" and commit the "necessary means" to the military campaign.
On Tuesday, Gaddafi said in an audio message broadcast by Libyan state television that he would fight to the death.
The North Atlantic block has sought more support from its members for the bombing campaign in Libya, given that the alliance's air power has been stretched by the latest strikes.
With only half of the 28 NATO countries taking part in the mission, Anders Fogh Rasmussen, the NATO secretary-general and Liam Fox, the British defence minister, called on member states to step up their participation.
Sweden announced on Wednesday that it will extend the mission of Swedish jets taking part in Libya reconnaissance missions by three months when it expires on June 22.
However, one of the alliance's most powerful members, Germany, has refused to take part in the mission and that looked unlikely to change on Wednesday.
"We will not change our position concerning the military action. We will not participate,'' Christian Schmidt, Germany's secretary of state, said.
Spain said it would not join the mission, despite now recognising the rebels.