Government forces in trucks disguised with rebel flags shelled opposition positions Tuesday near the strategic eastern oil town of Brega, killing eight rebel fighters and wounding dozens more, officials said.

In an audio message directed at a rally of thousands in the town of al-Aziziya, south of Tripoli, embattled ruler Muammar al-Qaddafi emphasized the importance of Libya's vast oil wealth to his regime, and called the civil war a battle "for our way of life."

Rebel forces have been pushing to seize the front-line town of Brega, which is home to an oil refinery and terminal, for nearly a week, but they say fields of land mines planted by Qaddafi's forces have slowed the advance.

The rebels are fighting in a residential area on Brega's eastern side and control about one-third of the town, spokesman Mohammed al-Rajali said.

Field commander Ahmed Maysawi said rebel forces were working to clear the mines so they can move forward while government troops are occasionally approaching in trucks disguised with rebel flags to shell rebel positions with mounted rocket launchers.

Mohammed Idris, a doctor at the hospital in the nearby city of Ajdabiya, said eight rebels were killed and dozens wounded Tuesday. That raised to at least 34 rebels killed in five days of fighting, according to Idris.

He said the rebels had taken four prisoners, and one dead government soldier had been taken to the rebel hospital. It is unclear how many other government soldier have been killed. The Libyan government rarely provides information on its casualties.

In his audio message, Qaddafi emphasized the importance of Libya's wealth and made a rare reference to the fuel shortages caused by Tripoli's international isolation that have made life hard in government-controlled areas.

"This battle is in our homes. It has affected our children's food, our oil, our oil fields," he said in a clip shown on state TV. "It cuts off electricity, it cuts off gas. This battle is for our children's food, for our way of life."

Some 5,000 people, mainly from the local Warshafana tribe gathered in the main square of al-Aziziya, around 30 miles south of Tripoli, and cheered wildly, waving green flags.

They chanted their support for Qaddafi and at the end of his speech fired dozens of AK-47s in the air, startling the scores of horses tribesmen had brought to the rally.

Rebels struggling to oust Qaddafi since the uprising against his rule broke out in February control much of Libya's east, but Brega, 450 miles southeast of Tripoli, has been under government control since early April.

The two sides have been locked in a stalemate with the rebels unable to advance beyond pockets in the west despite a NATO air campaign against Qaddafi's forces.

Last week, more than 30 nations including the United States gave the rebels a boost by recognizing their National Transitional Council as the country's legitimate government, potentially freeing up billions of dollars in urgently needed cash.

The International Committee of the Red Cross said Tuesday that medical services in Libya's western mountains are struggling with a flood of casualties from fighting.

Tuesday's statement said facilities lack medicine to treat patients and vaccines to deal with outbreaks of disease.

An ICRC delegation visited the region and provided bandages and other medical materials.

Arab and Berber rebels wrested control of much of the Nafusa mountains from the government weeks ago. The range stretches from the Tunisian border to within 60 miles of Tripoli.

But rebels have been unable to capture the strategic mountain town of Gharyan, which controls the approach to the capital.