A Lebanese Christian family were shocked to hear their son named last week as one of the alleged jihadists arrested for planning suicide bomb attacks.

The Lebanese army announced last Thursday that it had foiled "a plan to implement a series of suicide attacks" and arrested three people including Elie Warraq, 22, who used the name Abu Ali.

This was the first his family knew about his change in beliefs or his allegiance to militant ideology.

"We were so shocked when we heard the news, I haven't slept since. It's my son!" Warraq's father Tony said in an interview with AFP.

The army said the group were planning a series of attacks on army posts and residential areas.

"The investigation found they had pledged allegiance to terrorist organisations and participated in fighting in Syria and attacks against the army," the army statement said.

Warraq's family are devout Christians and supporters of the Lebanese armed forces, particularly since Warraq's 20-year-old brother is a soldier.

His father said: "Whenever I see on television that people are blowing up churches and mosques in Iraq and Syria, I wonder 'How could a human do such a thing?'

"But to hear your son is in the same category is very difficult. Am I hallucinating? I still can't believe it."

Warraq's family said he began to spend long periods away from home about 18 months ago. But his father said they had not suspected anything, adding that his son would still go to church on special occasions.

A security source told AFP that Warraq had visited Turkey twice, where it is thought that he crossed into Syria.

The news agency speculated that he could be the first Lebanese Christian to have joined the jihadists.

Last week's arrests follow a double suicide bomb attack on a Lebanese café on January 10 by Al Nusra Front, an Al-Qaeda-linked group. Nine people were killed in the incident.