Two American citizens killed in the Brussels terror attacks have been confirmed as a brother and sister from New York.
Alexander and Sascha Pinczowski had not been heard from since Tuesday's bombing at the Brussels airport.
Relatives say they were waiting to board a flight to JFK and that Alexander was talking to his mother on the phone when the line dropped.
In a tweet, Mayor Bill de Blasio expressed condolences and said the city will continue its part to fight terror "at every turn."
Two of our own lost in the #brusselsattack. In memory of the Pinczowski siblings, we will continue to stand up to terror at every turn.
— Bill de Blasio (@BilldeBlasio) March 25, 2016
Meantime, the mayor of Brussels tells Belgian media that a raid in the city Friday led to an arrest in connection to this week's bombings.
Belgian media had reported the sounds of explosions in the area during the raid, and says one man carrying a bag of explosive material was wounded and arrested.
The mayor says the latest police action is also linked to the arrest of a man in Paris on Thursday.
Officials say that man had a Belgian terror conviction, and connections with the suspected mastermind behind the Paris terror attacks last year.
Six others have been detained in raids around Brussels linked to the bombings.
It comes as U.S. government officials also confirmed Friday that a senior Islamic State leader was killed by U.S. forces.
Defense Secretary Ash Carter says Haji Iman was a well-known terrorist, who acted as the group's Finance Minister and played a key role in external affairs.
He is one of several Islamic State terrorists the U.S has killed this week.
Carter says Iman's death will hamper the terrorist organization.
Officials say Iman had been an original member of the Islamic State group dating back to its earliest iteration as al-Qaeda in Iraq.
U.S. Secretary of State John Kerry visited Belgium on Friday to pay his respects to the attack victims and take part in counter-terrorism talks with European Union officials.
During a news conference in Brussels, Kerry delivered a message to those behind the attacks.
"We will not be intimidated. We will not be deterred. And 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 this earth," Kerry said.
Authorities in Belgium have lowered the country's terror threat level one notch.
But they say another attack is "likely and possible."
Brussels Airport has canceled flights until at least Monday.