US Secretary of State John Kerry also said today that a number of Americans died in the attacks, which were claimed by the Islamic State jihadi group.
Kerry did not give a figure but a US official separately said two US citizens had been confirmed dead.
As forensic experts continued to sift through evidence, the Dutch foreign ministry announced that a brother and sister who lived in the United States and a woman from the central Dutch city of Deventer were among the victims.
"It's awful that these people were killed by a random act of terror."
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A Dutch newspaper said they were on the telephone to a relative when the bombs went off and the line went dead.
NOS named the other Dutch victim as Elita Weah, 41, who was on her way to her stepfather's funeral in the US.
"We can confirm David Dixon lost his life in the attacks which took place in Brussels on Tuesday 22 March 2016," the ministry said in a statement.
"We know of seven British nationals who were injured in the attacks -- three are still being treated in hospital."
His family issued a statement calling the news "terrible and devastating".
Dixon texted his aunt after the airport blasts to say he was safe, but happened to be on the metro system when a suicide bomber blew himself up.
"We express deep condolences over the death of our Chinese compatriot and strong condemnation on the criminal act of the terrorists," said the Chinese embassy on its website.
The family of 21-year-old Bart Migom, who was travelling to see his American girlfriend, had declared him missing, and the Belgian college where he was a student today said he was one of the victims.
Along with the 31 dead, 300 were injured, 61 critically.
Identification is proving slow, complicated by the violence of the explosions and because many of the victims were foreigners, police told RTBF television.