BEIRUT (REUTERS) - Lebanon's army on Wednesday arrested a senior Al-Qaeda-linked militant described by security sources as a "mastermind of car bombs" that targeted Shi'ite areas of the country.

Security sources said the arrest of the "terrorist" Naim Abbas could help uncover radical jihadi cells in Lebanon, which have been ratcheting up attacks against the army and against the political and militant Shi'ite group Hizbollah.

The surge in violence in Lebanon is linked to the three-year conflict in neighbouring Syria, with sectarian tensions between Sunni and Shi'ite Muslims rising on both sides of the border.

Hours after Abbas's arrest, security forces found two booby-trapped cars - one loaded with 100 kg of explosives in the Corniche al-Mazraa district of central Beirut and another in the village of Arsal, near the border with Syria.

"It was he (Abbas) who confessed and gave the location of these two cars. So far two cars have been discovered but many more will follow," a security source told Reuters.

Abbas, a Palestinian, was snatched from his house in a Beirut suburb in a special operation led by the Lebanese army early on Wednesday morning.

Security sources said he played a role in four car bomb attacks targeting Shi'ite suburbs of southern Beirut and two more in the mostly Shi'ite town of Hermel, all Hizbollah strongholds. Scores of civilians were killed in the attacks.

"He drove the suicide bombers to the southern suburbs. He is the mastermind of car bombs, he is as important as Majid al-Majid," another source said, referring to another top militant.

Majid bin Muhammad al-Majid, seized by the army in December, was leader of the Abdullah Azzam Brigades, which are named after a founder of Al-Qaeda and associate of the late Osama bin Laden.

They were formed around 2005 as a spinoff from Al-Qaeda in Iraq.

Lebanon, which is still recovering from its own 1975-1990 civil war, has been struggling to stem the spillover of violence from Syria.

Hizbollah has sent fighters and advisers to help its ally President Bashar al-Assad, a member of the Shi'ite-derived Alawite minority, against mainly Sunni rebels who have become dominated by Islamist fighters.