U.S. Secretary of State John Kerry says that Americans were among those killed in Tuesday's terrorist attacks in Belgium's capital, which killed at least 31 people and injured hundreds more.

Speaking in Brussels on Friday, Kerry said he was grieving with "the loved ones of those who have been very cruelly taken from us — including Americans."

The director of the State Department Press Office has since specified that two U.S. citizens were killed in the attacks.

It's the first confirmation of American deaths in the attacks.

More details about the American victims aren't yet known.

Tuesday's bombings struck the Brussels airport and a metro station, and were later claimed by ISIS. Some of the suspected bombers have been identified by police; others are still being pursued by authorities.

Belgian authorities haven't released details about any victims in the attack, but some information has been made public by other countries and by individuals.

Here's some of what we know so far about the attack's victims:

  • Alexander and Sascha Pinczowski: The Dutch siblings, who lived in New York City and attended Marymount Manhattan College, died in the explosions at the airport. Former U.S. Ambassador James Cain — the father of Alexander's fiancee, Cameron Cain — confirmed the deaths on behalf of the Pinczowski family. "The siblings were on the phone with a relative while at Brussels airport when the phone went dead," The Associated Press writes.
  • David Dixon: The British man, originally from Nottingham, had lived in Brussels with his partner for a decade, the BBC reports. Dixon and partner Charlotte Sutcliffe had a young son. He had texted his aunt saying he was safe after the airport blasts, but was missing after the subsequent explosion at a metro station, the BBC reported earlier.
  • Adelma Tapia Ruiz: The Peruvian national died in the airport attack, her husband and 4-year-old twin daughters were saved by chance, The Associated Press reports. Her Belgian husband, Christophe Delcambe, had taken the girls out of a line to play for a moment when the explosion struck. Her friend Lady Jouan tells All Things Considered that Ruiz was an extrovert who loved to cook.
  • Leopold Hecht: The 20-year-old student at a Belgian university died in the Maelbeek subway station bombing, according to a statement from the rector of Universite Saint-Louis – Bruxelles.
  • Olivier Delespesse: The New York Times reports that Delespesse, who died in the subway attack, worked in public service for French-speaking Belgium and was known to his coworkers as playful and approachable.
  • A Dutch citizen from the eastern city of Deventer died in the attacks, according to the Netherlands' foreign minister.
  • A French citizen died in the attacks, according to the French foreign ministry.
  • A Chinese national, surname Deng, died in the attacks, according the the Chinese embassy in Belgium, as translated by the news agency Xinhua.
  • Two American citizens: At this time, there's no information as to the Americans' identity.

Copyright 2016 NPR. To see more, visit http://www.npr.org/.