More than 100 tanks were seized from a militia loyal to Libya's ousted leader Moammar Gadhafi as authorities hunted the perpetrators of a double car bombing, the interior ministry said on Thursday.

A ministry official said an investigation into the attacks on Sunday helped to detect the militia which posed as "revolutionaries" and was housed in barracks in Souk al-Ahad near Tarhuna, 60 kilometres (35 miles) southeast of Tripoli.

"More than 100 tanks and 26 missile launchers were seized" from the militia, Abdelmonem al-Hur, spokesman for the interior ministry's High Security Committee, told a news conference.

The car bombs killed two people and wounded four others in Tripoli in the dawn attacks which took place as Muslims prepared to attend prayers on the first day of the Eid al-Fitr holidays.

The spokesman said that one person was killed and eight others were wounded as security forces arrested the militia's leader, Khaled Ibrahim Krid, in an operation on Wednesday.

Thirteen people were also arrested in the operation, while three others escaped.

The interior ministry had on Wednesday reported clashes between Tarhuna members of the security services and suspects allegedly involved in Sunday's blasts.

The pro-Gadhafi militia known as Katibat al-Awfiya (Brigade of the

Faithful) was known internally as the "Brigade of Martyr Moamer Gadhafi," who was killed last October, according to Hor.

"We believed the Katibat defended Libya and the revolution, but it turned out to be contrary," he said.

The same militia stormed Tripoli airport in early June blocking air traffic for several hours in protest at the "kidnapping" of one of their leaders, before authorities dislodged them and regained control of the facility.

Hor acknowledged that Libya's security forces had been infiltrated by supporters of the former regime and said a committee has been formed to investigate.

On Thursday, Libya's national assembly met in a closed session to discuss insecurity across the country. Interior Minister Fawzi Abdelali reportedly came in for heavy criticism for "lax" security.

The interior ministry said on Monday that Libyan authorities had arrested the key suspect behind the deadly car bombings and three of his accomplices, identifying them as Gadhafi loyalists.

"The key suspect was arrested and admitted that he was directly responsible along with four other people," Deputy Interior Minister Omar al-Kadhrawi told reporters. Police were hunting for a fifth suspect.

Kadhrawi said the key suspect had testified that he orchestrated the bombings to avenge the death of his brother in a NATO raid during last year's revolt which toppled Gadhafi's regime.

The first car bomb on Sunday blew up near a military academy on Omar al-Mokhtar Avenue, a main thoroughfare in the capital, while the other exploded near the interior ministry. (AFP)