TRIPOLI - Gunfights broke out in the Libyan capital Tripoli on Friday between supporters of deposed leader Muammar Gadhafi and forces of the National Transitional Council (NTC), raising fears of an insurgency against the country's new rulers.

Nearly two months since seizing the capital, Libya's National Transitional Council has failed to capture the final holdout towns still under the grip of Gadhafi's supporters. The ousted leader has repeatedly vowed to lead an uprising.

Friday's battles appeared to be isolated and and involve only dozens of pro-Gadhafi fighters, but it was the first sign of armed resistance to the NTC in the city since its rebel brigades seized the capital and ended Gadhafi's 42-year rule in August.    

Hundreds of NTC fighters in pick-up trucks shouting "Allahu Akbar" (God is greatest) careered towards the Abu Salim neighbourhood, a centre of support for Gadhafi, and the two sides exchanged automatic and heavy machinegun fire.

Local people told Reuters at the scene that a group of up to 50 armed men had appeared in Abu Salim earlier in the day and had chanted pro-Gadhafi slogans. NTC men said fighting also broke out in three other nearby neighbourhoods.

"Gadhafi told them in a message last night to rise up after Friday prayers," said one NTC fighter, Abdullah. "That's why these few people have come out and are causing this problem."

Since he went into hiding after rebel forces captured Tripoli on August 23, the former leader has released a number of audio recordings calling on loyalists to fight back.

NTC fighters dragged one man out of an apartment block in Abu Salim, a traditional bastion of support for Gadhafi. As he was kicked and punched, one of the NTC men plunged a knife into the prisoner's back. It was unclear if it was a fatal blow.  

The captured man had been armed with a rocket-propelled grenade, said NTC fighters. The interim government's forces have been criticised by human rights groups for their treatment of prisoners. Reuters saw at least two other captured gunmen taken away in pickup trucks being punched and kicked in the face.

Dominated by apartment blocks, Abu Salim was the last part of the capital to fall to the NTC when its forces took the city after six months of civil war.

The NTC fighters were met by volleys of machinegun fire as they went from house to house searching for remaining Gadhafi gunmen. Shooting died down later in the afternoon.

"Some Gadhafi cells came out on the streets with guns today after prayers but, as you can see, our forces have the situation under control," said a senior NTC official at the scene under heavy protection, Mahmoud Abdul Aziz.

"All families are safe. If Gadhafi is still at large we won't see peace but we will slay that beast."

A spokesman for the NTC in the eastern city of Benghazi dismissed Gadhafi's armed supporters in Tripoli as a "fifth column" trying to destabilise the country.

"The other thing I hear that is disturbing is that the fifth column has been doing some drive-by shootings around Tripoli today. These are loyalists trying to wreak havoc," he said.

Diplomats told Reuters there were drive-by shootings near the Radisson hotel, where some senior NTC officials and Western diplomats are staying.

Gadhafi supporters appear to have set Friday as the date for a new uprising. A pro-Gadhafi Facebook group called October 14 bears a green Gadhafi flag and calls for an "intifada (uprising) of the free Libyan people." It has more than 1000 followers.