BEIRUT (AFP) — A "terrorist" cell said to be behind three bomb attacks in Lebanon was seeking revenge for the army's victory over an extremist Islamist group last year, a security official said on Monday.

"The cell is linked to Fatah al-Islam and some of its members came from that group," the official told AFP, referring to an Al-Qaeda-inspired militia which fought a 15-week battle last year against the army in a Palestinian refugee camp.

"So far the army is the sole target of attacks mounted by this cell and the operations they were planning target the army and internal security forces," the official said on condition of anonymity.

Six suspects were rounded up on Sunday but three have since been released.

The official said the cell was to blame for an attack on a military bus in the northern city of Tripoli on September 29, when four soldiers and three civilians were killed.

It was also responsible for an attack in the port city in mid-August which killed 14 people, including nine soldiers and a child, and the murder of a soldier in a bomb blast on an army intelligence post in Abdeh in May.

"Documents seized in two places searched by a joint force -- in Tripoli and Akkar -- show that the army and internal security forces were also their next target," he said.

Interior Minister Ziad Barud said that the breakthrough "does not mean that the threats have been eliminated. The security agencies remain on alert."

Ministry officials showed reporters an explosives belt, rifles, ammunition, bombs and guns that were found at the home of the sister of Abdel Ghani Ali Jawhar, a fugitive in the case.

The As-Safir newspaper reported that the cell was planning an attack on a Lebanese army bus and on internal security forces headquarters in Beirut.

The army ousted Fatah al-Islam fighters from the Nahr al-Bared camp near Tripoli in September last year after 15 weeks of fighting that left 400 people dead, including 168 soldiers.

However, Fatah al-Islam chief Shaker al-Abssi managed to flee and has vowed revenge attacks against the army.

Mahmud Azzam, 80, who was briefly detained at the weekend along with three of his sons, denied the family had any links to Fatah al-Islam.

"I have been a businessman for many years... and my sons worked with me. They didn't belong to any faction in the camp," Azzam, who owned candy stores in Nahr al-Bared, told AFP after his release.

He said his son Jihad was killed during the fighting in the camp but insists he was not involved with any militia and died in a shelling as he went out to buy bread.

Azzam said one of his sons, Mohamed, still remains in custody but that he had no political inclinations and was involved in teaching a children's folk dance group.

Source: AFP