A British man has been confirmed dead following the terror attacks in Brussels.
The family of David Dixon, 50, who was originally from Hartlepool but was living in the Belgian capital, said they had received "the most terrible and devastating news".
At least 32 people were killed and 270 injured when suicide bombs ripped through the airport and a Metro station on Tuesday morning.
A statement issued by the Foreign Office on behalf of Mr Dixon's family said: "This morning we received the most terrible and devastating news about our beloved David. At this most painful time our family would gratefully appreciate it if we could be left alone to grieve in private. Please respect our wishes."
The Foreign Office said officials know of seven British nationals who were injured in the attacks, with three still being treated in hospital.
Mr Dixon, an IT programmer, had been missing since the Metro blast, and his family previously said they were "anxiously waiting" and hoping for "good news" about him.
It was reported that Mr Dixon's aunt had texted him following the airport explosions and had received a message back from him saying he was safe.
But it is thought he then got on the Metro to go to work and got caught up in the attack.
Prime Minister David Cameron tweeted: "I am deeply saddened to hear David Dixon was killed in the Brussels attacks. My thoughts and prayers are with his friends and family."
Foreign Secretary Philip Hammond said he was saddened by the "dreadful news".
Police have raided Brussels neighbourhoods in an operation the mayor said was linked to Tuesday's attacks and to the arrest in the Paris suburbs of a man who may have been plotting a new attack in France.
Three people were detained, with two of them shot in the leg, the federal prosecutor's office said.
The operation was conducted in the Schaerbeek district, which was raided on Thursday night, as well as the neighbourhoods of Forest and Saint-Gilles.
Belgium's state broadcaster said one person was carrying a bag of explosive material.
Prime Minister Charles Michel skipped a wreath-laying ceremony at the Brussels airport with US secretary of state John Kerry because of the police operation.
Prosecutors said three of six people detained on Thursday in the investigation have been released.
Three terrorists died in Tuesday's explosions and a massive manhunt was launched to track down other suspects believed to be behind the blasts.
Belgian security services were hunting two men pictured with the suicide bombers shortly before the attacks and believed to be on the run.
One of the men was caught on CCTV carrying a large bag and walking with jihadist Khalid El Bakraoui moments before the bomb detonated, according to state broadcaster RTBF and France's Le Monde newspaper.
Another of the suspected killers, dubbed "the man in white", was pictured pushing a trolley through Zaventem Airport with Najim Laachraoui and Khalid's brother Ibrahim before they blew themselves up.
Meanwhile, a US official said at least two American citizens were killed in the attacks.
The news came as Mr Kerry was visiting Brussels to express his condolences to the Belgian people.
Authorities announced that Chinese, French, and Dutch citizens were also among the dead.
German prosecutors said they are investigating whether a Moroccan man detained in central Germany has any connection to the Brussels attacks.
Prosecutors in Giessen said the 28-year-old was picked up early on Thursday because he did not have valid ID. They said they found documents indicating that he had been in the Brussels area recently and seized a mobile phone that they are now evaluating.
They said officials established that he had previously entered Germany under various aliases and sought asylum, and that he is known to police in Italy.
Der Spiegel magazine and two public broadcasters are saying the man received two suspicious text messages on the day of the Brussels attacks.
Meanwhile, US defence secretary Ash Carter said US forces have killed a senior Islamic State leader, among several key members of the militant group eliminated this week.
He identified the senior IS leader as Haji Imam and described him as the group's finance minister. He said he was a "well-known terrorist" who had a hand in terror plots outside of Iraq and Syria.
He did not say whether the IS finance leader was killed in Syria or Iraq.
Mr Hammond tweeted: "Another step closer to defeating #Daesh with the death of Haji Imam. #CoalitionProgress continues."