Forces loyal to Moammar Gadhafi shelled a rebel-held city near the capital Saturday, as anti-government fighters seized an important oil port in the latest round of a bloody civil war that has tore Libya in two.

As Gadhafi's forces sent tanks into the city of Zawiya, which is just west of Tripoli, local forces attempted to ferry the wounded fighters to a make-shift clinic that was set up in a mosque. Rebels feared they would be killed if they went to a state hospital.

Meanwhile, in the port of Ras Lanouf, rebel forces were victorious in defeating government troops. The victory is part of a west-ward push toward Gadhafi's hometown of Sirte, where a serious clash could occur as Gadhafi holds sway with tribal leaders.

Earlier, rebels were celebrating the crash of a Libyan jet fighter as they continued to fight for control of key cities.

Witnesses say a Libyan jet fighter crashed near Ras Lanouf on Saturday, hours after rebel forces overtook the eastern oil port city. The cause of the crash could not immediately be determined.

Pro-Gadhafi forces have launched a number of air strikes on rebel targets, in an attempt to quash the nearly three-week-old uprising.

However, in a sign that the battle could rage for an extended period, Gadhafi's fighters retook Zawiya after a two-day attack.

Rebel blockades were overwhelmed by machine-gun fire and heavy mortar shelling Saturday morning. Witnesses who spoke to the Associated Press by telephone said the shelling caused damage to both government buildings and homes in the city, and also left several fires burning.

Residents huddled in their homes during the attack, which lasted several hours, listening to the sounds of gunfire and explosions. Clouds of smoke hung over parts of the city of 200,000 people when the fighting was done.

In the end, pro-Gadhafi forces were pushed from the main area of town, but they regrouped for a fresh assault later in the day and took the centre.

With hundreds already reportedly killed, the international community is left questioning how deadly the civil war could become.

"We will fight them on the streets and will never give up so long as Gadhafi is still in power," one of the rebel fighters told AP, speaking on condition of anonymity out of fear of reprisals.

Gadhafi attempting to fortify capital

Reporter Lama Hasan, speaking from the rebel-held town of Benghazi, said Gadhafi will send his forces to rebel-held towns close to the capital in an attempt to fortify his control there.

"Zawiya is seen as a crucial town for Gadhafi because it used to be one of the rebel towns and that is where the battle is taking place right now," Hasan told Â鶹´«Ã½ Channel in a telephone interview Saturday morning.

"So that is how Gadhafi is dealing with it. He is sending his forces, especially to towns in the west so he can try and liberate them, especially towns close to the capital where he still has the upper hand."

Losing Zawiya marks the second setback for rebels in as many days, after a massive explosion Friday at a munitions depot in Benghazi killed at least 26 people. The blast flattened an area the size of three football fields, wiping out buildings, cars and trees, which were still smouldering early Saturday.

While it was not immediately clear what caused the blast, many rebels believe Gadhafi and his forces destroyed the source of weapons and ammunition they will need as they continue their march westward toward the capital.

Hasan said many of the dead, from the explosion and other bloody battles throughout the country, are being brought to Benghazi for their funerals, during which they are hailed as martyrs.

She said many men turn up at the city's old Supreme Court building every day, demanding arms so they can "go to the front lines to join other rebels to fight all the way to Tripoli, the capital of Libya, so that they can free that and other towns in the west and unite Libya."

She added: "The fact that there are bloody battles still going on in pockets of the country is not stopping the men here or deterring them from joining in."

Canadian doctor travels with rebels

Dr. Fathi Abuzgaya, an orthopedic surgeon from Pickering, Ont., has been helping those wounded in the Benghazi explosion. Abuzgaya said there were a lot of gruesome injuries, and treating patients has been a challenge because of the lack of medical supplies.

"It is challenging. We have received some equipment last night from Egypt," he told Â鶹´«Ã½ Channel on Saturday. "We are still waiting for more to come in the next day or two."

Abuzgaya said that he will travel with rebel forces as they continue to press toward Sirte, where Gadhafi has established a large contingent of fighters.

"The distance is too long for the injured to reach Benghazi," he said. "All those injured people, without a sophisticated ambulance transfer system, will not make it if we wait in Benghazi."

Rebels take Ras Lanouf

Despite the setbacks, rebels managed to capture the key oil port of Ras Lanouf after a fierce battle with pro-Gadhafi forces late Friday. The port is about 140 kilometres west of the Gadhafi stronghold of Sirte.

The pre-Gadhafi red, black and green monarchy flag, which rebels have been flying in towns they have captured, could be seen flying over Ras Lanouf's oil facilities early Saturday.

One of the rebels, Ahmed al-Zawi, said rebels were able to send Gadhafi's forces fleeing when local residents joined the opposition cause.

"We won the battle when the people joined us," said al-Zawi, who reported that 12 rebels were killed in the fighting. However, a hospital official in the nearby town of Ajdabiya said only five rebels were killed, with 31 others injured.

Al-Zawi said rebels will regroup after their victory in Ras Lanouf and will soon begin moving toward Sirte.

With files from The Associated Press