Back-up terror cell 'watched Brussels bombings' – and is primed to launch MORE attacks

BACK-UP Jihadis who coolly watched carnage unfold in Brussels are ready to launch their own deadly attacks, reports say.

DEVASTATED: Children pay tribute as Belgium hunts terror suspects

It has emerged that a second suspect has been linked to the Metro suicide bombing, after a man was spied on CCTV with Khalid el-Bakraoui before he blew himself up.

Cops are also tracing two cars thought to have followed the three attackers to the airport.

Witnesses reported a second terror cell watched the attacks on Tuesday, which killed 31 people and injured 271. 

Up to seven terror suspects are reportedly being hunted in the aftermath of the attacks. 

Reports say the group responsible for the Brussels carnage is the same "super cell" as that behind the wave of deadly attacks in Paris in November.

Belgian authorities are trying to trace a black Audi and Renault Clio seen at the airport.

MYSTERY: The identity of the man in white is still unknown

It is possible the mystery "man in white" was driven away from the airport in one when his suicide bomb failed to detonate.

Ibrahim el-Bakraoui, 29, and 24-year-old Najim Laachraoui – the suspected bomb-maker behind the Paris attacks – were the two attackers killed in the airport blasts.

It was initially thought that Laachraoui had escaped the blast and was the "man in white" but Belgian securiy services retracted that.

Forensic teams identified him from DNA remains found in the terminal.

The manhunt for suspects comes as authorities fear follow-up attacks.

TRIBUTES: San Francisco City Hall lit up in colours of Belgian flag

It is understood the Audi is registered to a 22-year-old of Turkish origin, who travelled to Saudi Arabia last year.

Authorities said that “at least” one other person with direct links to the attack was still on the run, while several others may be on the streets.

It has been reported that the bombing was scheduled for Easter Monday, but brought forward after the arrest of fugitive Salah Abdeslam on Friday last week.

He has today denied knowing about the Brussels carnage in advance, vowing to "explain himself" when he is extradited to France.

The Paris terror cell is thought to have had 30 members, 11 of whom are dead, with 12 detained and seven still at large.