Cairo/Benghazi (Agencies): Anti-government protest demonstrations continued on Sunday in Libya for the sixth straight day, with the flashpoint city of Benghazi in the north east reporting the highest death toll.

With journalists barred from travelling to Benghazi, and internet and mobile phone connections reportedly cut by the government, obtaining reliable details about the situation in the country ruled by Muammar Gaddafi since 1969 is difficult.

But above 200 people have been killed over the past two days, a doctor in Benghazi, the country's second city, told Al Jazeera TV.

Ali Belqasem told the Doha-based channel that bodies showed they were either gunshot in the head or chest. "All young, all unarmed," said Belqasem.

There were no confirmed reports about protests in the city, whilst activists said in online posts that they have also lost all contact with people in Benghazi.

The London-based news website Libya al-Youm, which put the death toll in Banghazi at 208, said the army had used rocket-propelled grenades and other intense weapons on protesters.

One eyewitness told the reporters that soldiers were not Libyans but rather mercenaries from Mali.

Demonstrations against the regime of Gaddafi began on Tuesday evening in Benghazi, Libya's second largest city after the capital Tripoli.

The northern coastal city of Misurata, and Al Bayda town, was also the scene of demonstrations.

Emboldened by the successful revolutions in Tunisia and Egypt, thousands of Libyans have been calling for the expulsion of Gaddafi, who has been in power for 41 years.

Meanwhile, neither Moamer Gaddafi nor his family will depart Libya, the Asharq al-Awsat newspaper on Sunday quoted sources within the clan as saying.

Libya, a major oil producer, has a population of nearly six million people.

Gadhafi’s son warns of civil war

The son of longtime leader Moammar Gadhafi warned in a nationally televised address that anti-government protests that have jolted Libya for six days might lead to a civil war that could send the country's oil wells up in flames.

Appearing on Libyan state television after midnight on Sunday, Seif al-Islam Gadhafi said the army still supported his father, who was leading the fight, although he added that some military bases, tanks and weapons had been seized.

"We are not Tunisia and Egypt," the younger Gadhafi commented, referring to the successful uprisings that toppled longtime regimes in Libya's neighbours.

He acknowledged that the army made mistakes during protests because it was not trained to tackle with protesters but added that the number of dead had been exaggerated, giving a death toll of 84.

US expresses concern

The United States has expressed grave concern over the ongoing situation in Libya, where brutal crackdowns on pro-democracy protestors have so far took nearly 200 lives.

"The United States is gravely concerned with disturbing reports and images coming out of Libya," stated State Department spokesman PJ Crowley.

While the US is working to ascertain the facts, but it has received multiple credible reports that hundreds of people have been killed and wounded in several days of unrest and the full extent of the death toll is unknown, he said.

"We have raised to a number of Libyan officials, including Libyan Foreign Minister Musa Kusa, our strong objections to the use of lethal force against peaceful demonstrators," Crowley added.