Lebanon's army on Wednesday arrested a commander of a group loyal to Al-Qaeda that in November claimed a twin suicide attack against the Iranian embassy in Beirut, killing 25 people.
"After careful follow-up and monitoring, the (army) intelligence directorate in Beirut arrested the terrorist Naim Abbas, a commander of the Abdallah Azzam brigades," the army said in a statement.
The Abdallah Azzam Brigades, which describes itself as loyal to Al-Qaeda, has been listed by the United States as a terrorist organisation since 2009.
The arrest of its Saudi leader Majid al-Majid was announced in early January. He died days later from poor health.
Abbas' detention also follows the indictment of a Sunni Muslim sheikh, Omar Ibrahim al-Atrash, in connection with two suicide bombings in southern Beirut, a Hezbollah stronghold, that killed at least six people.
In a late January army statement on Atrash, the army had said Abbas was among three "wanted men" loyal to the Abdallah Azzam brigades and Al-Nusra Front, Syria's Al-Qaeda branch.
In recent months, Lebanon has seen a string of deadly attacks linked to Syria's war, claimed by Al-Qaeda-linked groups including the Abdallah Azzam brigades.
Though Lebanon is officially neutral in Syria's conflict, the country is deeply divided over the rebellion against President Bashar al-Assad.
Shiite Hezbollah supports his regime and has sent thousands of fighters into Syria to back his troops.
Sunnis support the anti-Assad revolt, and Sunni jihadists have carried out numerous car bomb and suicide attacks against Hezbollah-dominated areas, killing civilians.