Brussels attacks: Najim Laachraoui confirmed as 2nd bomber

Brussels: Belgium's federal prosecutor confirmed on Friday that Najim Laachraoui was one of the two suicide bombers who struck Brussels airport this week in a series of attacks which left 31 people dead.

Read:Brussels attacks: Belgium publishes surveillance picture of three suspects

A statement from the prosecutor's office also linked Laachraoui to November's Paris carnage in which 130 people died, saying his DNA was found on a suicide vest and a piece of cloth discovered at the Bataclan, the concert hall where 90 people were killed.

Police also found his DNA on a bomb at the Stade de France.

Read:Terrorist in ‘advanced stages’ of plotting attack in France arrested

Meanwhile, the top members of Belgium's embattled government are facing criticism over its counter terrorism efforts since -- and before -- the November 13 Paris attacks that killed 130 people and that authorities believe were plotted from Belgium.

American Secretary of state, John Kerry, also said that the U.S. and other countries had already scheduled meetings with Belgium prior to the attacks about improvements they could make to their laws, intelligence collection and attempts to blunt the radicalization of youth.

The Islamic State group has claimed responsibility for the attacks in Paris and Brussels, and Kerry lashed out at the extremist group.

"We will not be deterred," he said. "We will come back with greater resolve - with greater strength - and we will not rest until we have eliminated your nihilistic beliefs and cowardice from the face of the Earth."

Authorities also announced that American, British, Chinese, French and Dutch citizens were among the dead.

A manhunt has been underway since Tuesday for one of the Brussels airport attackers who was recorded on a surveillance video and fled the scene. Prosecutors have not said how many attackers there were in total, or how many accomplices might be at large.

Belgian prosecutors said raids Thursday night targeted central Brussels, Jette and the Schaerbeek neighbourhood, where police had earlier found a huge stash of explosives and bomb-making material in an apartment used by the Brussels attackers.

Read: Two Americans killed in Brussels bombings, Kerry offers help

French counter terrorism police also detained a man Thursday who officials say was in the advanced stages of an attack plot.

Officials told The Associated Press that the suspect, Reda Kriket, 34, had a past Belgian terrorism conviction and was linked to the suspected ringleader of the Paris attacks, Abdelhamid Abaaoud.

Elsewhere, Belgium's nuclear agency said it has withdrawn the entry badges of some staff and denied access to other people recently amid concern the country's nuclear plants could be a target for extremists.

Read: Suspect arrested in new anti-terror raid, slightly hurt in Brussels anti-terror raid

The move at some plants "is not necessarily linked with the terrorist attacks," said nuclear control agency spokeswoman Nele Scheerlinck, noting the decision to deny access usually takes weeks.

Immediately after Tuesday's attacks, security was boosted around the country's nuclear sites and hundreds of staff were sent home.

Read: Brussels: 35 killed in terror attacks, Islamic State claims responsibility

Last month, authorities said searches in the wake of the Paris attacks uncovered video linked to a person working in Belgium's nuclear industry.

Belgian media reported this week that Brussels attackers Ibrahim and Khalid El Bakraoui had video recordings of the home of a senior official at the Mol nuclear waste facility in the Flanders region. It's unclear why.