A second bomber involved in the Brussels metro terror attack may be on the run, according to reports.
Belgian police are hunting a man caught on CCTV carrying a large bag and walking with jihadist Khalid El Bakraoui shortly before the bomb detonated, according to state broadcaster RTBF and France's Le Monde newspaper.
It comes as security services are already scouring the country for another of the suspected killers, dubbed "the man in white".
Wearing a distinctive black hat and white coat, he was captured on CCTV pushing a trolley through Zaventem Airport with Najim Laachraoui and Khalid's brother Brahim moments before they blew themselves up.
Meanwhile, the family of Brussels-based David Dixon, 53, who is originally from Hartlepool and has been missing since the metro blast, said they are "anxiously waiting" and hoping for "good news" about him.
It has also been reported that the El Bakraoui brothers were plotting an attack on a nuclear power facility, and brought forward the Brussels attacks following the arrest of Paris attacker Salah Abdeslam.
The brothers planted a hidden camera in front of the home of the director of research and development at the Belgian nuclear programme, the newspaper La Derniere Heure reported.
The footage showed the nuclear boss's comings and goings and prompted investigators to conclude the terrorists "could have put national security in danger like never before", the paper added.
The Belgian authorities said at least 32 people were killed and 270 injured in the three suicide bomb attacks in Brussels on Tuesday morning, and the death toll could rise.
And they have confirmed the Brussels bombings, which Islamic State has claimed responsibility for, were linked to the Paris attacks in November.
Khalid is believed to have used an assumed name to rent a house in Charleroi in Belgium which was used as a hideout for the Paris attackers.
An international warrant was out for his arrest and police had been searching for him since December.
As the manhunt continues, Home Secretary Theresa May is joining counterparts from the European Union for an emergency meeting in Brussels to discuss ways to fight terrorism.
Arriving at the meeting, Mrs May said the killings were "cold-blooded and sickening attacks".
She added: "Obviously investigations are still ongoing, but we know that those responsible - Daesh - seek to divide us and harm our way of life and the UK stands ready to support Belgium in any way it can to unite, to defeat these terrorists.
"We will give Belgium the support it needs but our message is clear: The terrorists will not win."
Meanwhile, Downing Street said six UK citizens had been injured in the twin attacks, four of whom have been discharged from hospital and two are still receiving treatment.
In a statement, Mr Dixon's family said: "This is clearly a difficult time for our family and we are anxiously waiting for more information about our dear David.
"We are asking for our privacy to be respected during this time. We kindly ask for the media not to contact any members of our family in Belgium or the UK. We continue to hope for good news about David."
Flights to Brussels airport have been suspended until Monday, the airport said.
On Thursday, Belgium lowered its alert to the second-highest level, but said that another attack is still "likely and possible."