As demonstrations in Libya intensified Sunday, it appeared that Libyan leader Muammar Gaddafi is losing control of the country he has ruled for over 40 years.

On Sunday evening it was reported that the anti-government protests had spread to the capital Tripoli, which until then had not been affected by them. Al-Jazeera reported heavy gunfire exchanges in the center of the Libyan capital between thousands of demonstrators who gathered in the streets and supporters of Gaddafi. Eyewitnesses also reported the use of tear gas against demonstrators.

Also on Sunday, Sheikh Faraj al Zuway, leader of the Al-Zuwayya tribe in eastern Libya (a tribe which lives south of Benghazi), threatened during an interview with Al-Jazeera to cut oil exports to Western countries within 24 hours unless authorities stop what he called the “oppression of protesters.”

Akram Al-Warfalli, a leading figure in the Al Warfalla tribe, one of Libya's biggest, told Al-Jazeera: “We tell the brother (Gaddafi), well he's no longer a brother, we tell him to leave the country.”

Earlier Sunday in the city of Benghazi, members of a Libyan army unit reportedly told residents of the city that they deserted, liberated the city from forces loyal to dictator Gaddafi and joined the public protest against Gaddafi's rule. According to local hospitals, soldiers arrived for treatment, following clashes with Gaddafi's personal security staff.

The action came after at least 50 people were killed and 100 others were seriously wounded in afternoon and evening clashes. An emergency-room doctor said most of the dead had been shot.

Witnesses in Benghazi claimed that only one brigade did not join the demonstrators. It was also reported that the protesters climbed on top of tanks and that many of them were armed with rifles and machine guns which they had looted from the deserted tanks.

Meanwhile, Gaddafi’s son, Saif al-Islam Gaddafi, went on state television late Sunday night and addressed the country’s residents for the first time since the protests began.

In his speech, Gaddafi warned that Libya was on the verge of civil war and said that the protests against his father's rule were a foreign plot. He also pledged a new constitution and new liberal laws, saying the north African country was at a crossroads.

Gaddafi’s son warned that any uprising would be ruthlessly suppressed. “We will continue to fight until the last moment, until the last bullet is fired,” he said, while admitting that the local police erred in its behavior towards the demonstrators, attributing this to the fact that the officers had never been properly trained in handling mass demonstrations.

Gaddafi also dismissed reports by groups such as Human Rights Watch, which have placed the death toll from the protests at over 200. He claimed that only 84 people have died in the demonstrations.

Meanwhile, there were unconfirmed reports Sunday night that Muammar Gaddafi had fled the country to Venezuela. His son, however, dismissed those reports as well.

“My father is in Libya and is supported by his army,” he said.