Gary Mitchell, Sky News Online
Embattled dictator Colonel Muammar Gaddafi has made a surprise appearance before supporters in Libyan capital Tripoli, telling people: "Prepare to defend Libya."
He warned crowds gathered in Green Square that he would "burn all of Libya" if he was not supported by his people.
"We will defeat any outside attempt to overturn our country," he said.
Col Gaddafi urged his followers to"keep dancing, keep chanting", adding: "Libyan people love me."
It is not clear if the speech aired on state TV was live or pre-recorded.
The tirade follows days of anti-government protests which have left hundreds dead. Earlier, security forces reportedly opened fire on protesters in Tripoli, killing at least five.
The clashes broke out in the Janzour district of the city as demonstrators increased the pressure in Col Gaddafi's stronghold. Shots were also heard in the Fashloom area of Tripoli.
In his fourth address this week, Col Gaddafi vowed to triumph over his enemies and called on people to guard the country and its oil reserves.
He also appeared to promise to open weapons arsenals "when necessary" and arm supporters against "the enemy".
The leader, who alternated between blowing kisses and shaking his fist during the tirade, said: "Muammar Gaddafi is among you. I stand among the people and we will fight and we will kill them if they want."
Meanwhile, the US is said to be considering closing its embassy in Tripoli.
But he appears to be increasingly isolated, with some areas of the city coming under the control of opponents.
"Some areas are under opponents' control - other areas, mainly those around the Bab al-Azizia area (where Gaddafi lives), are under Gaddafi's supporters' and army's control," one resident said.
Campaigners outside the Libyan embassy in central London told Sky News that friends and relatives in the country had spoken of "blood on the streets", with many residents in Tripoli afraid to leave their homes.
Protesters have reported further gains, having already taken over in Libya's second city Benghazi, and they are said to be in charge of key Libyan oil and product terminals east of the capital.
Opponents have seized the eastern oil terminal town of Brega, where soldiers defected to help protesters.
Three towns in the Western Mountains region south-west of Tripoli have also escaped central control.
Some of the worst bloodshed has been in Zawiya, 30 miles west of the capital, where troops opened fire with automatic weapons on a mosque where residents had been holding a sit-in.
The mosque's minaret was blasted with an anti-aircraft gun. A doctor said he saw 10 dead bodies and around 150 wounded but another estimate put the death toll at 23.
Zawiya, a key city close to an oil port and refineries, is the nearest population centre to Tripoli to fall into the hands of the anti-Gaddafi rebellion.
Across the country, rebels have celebrated seizing power by showing off the tanks, armoured vehicles and weapons they had taken from security forces.
n the eastern coastal city of Tobruk, tanks lay abandoned on the street after soldiers defected. One told Sky News: "Gaddafi is finished."