A timeline of the way events unfolded during and after the attacks on the Belgian capital.
Sources say the terrorists blew up ammonium nitrate bombs.
Ibrahim El Bakraoui and younger brother Khalid were no strangers to police prior to Tuesday's suicide bombings in Brussels.
Passengers and staff at Zaventum airport react to the re-opening of the departure hall that was bombed in the Brussels terrorist attack.
Under extra security, the Brussels Airport reopened its departure hall Sunday for the first time since deadly Islamic extremist attacks in March.
Mason Wells, one of the Mormon missionaries hurt in the Brussels terrorist bombings, has returned to his home in Sandy, Utah.
The March 22 bombings of Brussels airport and subway killed more than 30 people.
The revelation came as the prosecutor formally charged Mohamed Abrini in relation to the Brussels attacks.
Mohamed Abrini, 31, was arrested and charged, along with three other men, with participating in "terrorist murders."
Another suspect was arrested over links to the Brussels bombings, Belgian authorities said Saturday as armed police swooped on a city suburb.
Belgian prosecutors confirmed the arrest of multiple terror suspects, including Mohamed Abrini who is believed to be the 'man in the hat' seen in Brussels airport.
Several arrests were made Friday in connection with the Brussels bombings, Belgian officials said.
Belgian prosecutors previously said the suspect had fled the airport just before the two blasts hit and left behind a large bag.
Najim Laachraoui blew himself up in the Brussels airport in March.
The U.S. TSA chief witnessed firsthand the devastation of the deadly bombings at the Brussels airport and subway and is motivated to improve security.
The bodies of a American couple killed in the Brussels attacks have arrived back in Kentucky.
Brussels airport reopened to a thin stream of passengers on Sunday, 12 days after suicide bombers destroyed its departure hall and killed 16 people.
Authorities charged a third suspect Saturday in connection with a foiled French terror attack, according to the Belgian federal prosecutor.
Photographer Ketevan Kardava reunited this week with Sebastien Bellin, the victim of the Brussels terror attack she photographed that terrible day at Brussels airport.
A Texas woman married to an Air Force officer was identified Wednesday as the third American killed in last week's Brussels terrorist attacks.
A Belgian newspaper released photos showing the destruction inside Zaventem Airport caused by the bomb attack on March 22.
The French national charged Wednesday with plotting a terrorist attack had an arsenal in his apartment.
A laptop used by one of the Brussels bombers contained "alarming" images of the Belgian prime minister's home and office, an official said Wednesday.
Mason Wells, 19, and Joseph Empey, 20, were in fair condition at the University of Utah Hospital, church and hospital officials said on Tuesday.
Belgium's crisis center also said Tuesday that the number of victims is back down to 32 after it was discovered some were counted more than once.
The only suspect directly charged in connection with the terror attacks in Brussels has been released.
Emergency responders received a standing ovation after a prayer service was held to commemorate the victims of Brussels terror attacks.
Terrorists were apparently trying to steal radioisotopes, and some experts say detonation of a "dirty bomb" is inevitable.
Belgian police issued video from Brussels airport surveillance cameras in a new appeal for information about a suspect they wish to identify.
As the world mourns the Brussels attacks, it's important to remember those elsewhere who recently lost their lives at the hands of terrorists.
It looks like the "man in white" is still out there.
The toll from the bombings also climbed to 35 early Monday.
Two more Americans were killed in last week's attacks, bringing the number to four, the State Department confirmed Sunday.
Police in Brussels surrounded a group of demonstrators about 500-strong who descended Sunday on a memorial for those killed in terror attacks earlier in the week.
Pope Francis urged the world in his Easter message on Sunday to use the "weapons of love" to combat the evil of "blind and brutal violence", following the attacks in Brussels.
Five days after 28 people were killed in the Brussels terror attacks four victims remained unidentified — an agonizing delay for families waiting on news about their loved ones.
Joseph Empey, who was dropping off another missionary at the airport when the blast knocked him unconscious, said he is "feeling good" despite his wounds.
His wife said doctors are hopeful they can start to wake him up later Saturday — just in time for Easter.
Justin and Stephanie Shults had not been heard from since the terror attacks at an airport in Belgium.
Faycal Cheffou was detained Thursday night in Brussels, but is the first to face charges in relation to the terror attacks in the Belgium capital.
Flights at Brussels Airport will not resume until at least Tuesday in the wake of this week's deadly terror attack.
Francois Hollande said the network responsible for attacks in Brussels and Paris is in the process of being wiped out, but other groups remain.
Komal Kaur heard 3 or 4 gunshots and spoke of the moment police approached the injured man with caution in the Schaerbeek district of Brussels.
Mason Wells recounts dodging death after two bombs exploded at Brussels airport, this after witnessing the aftermath of the Boston Marathon attacks.
Sascha and Alexander Pinczowski were world travelers who friends described as kind-hearted and quick to make those around them laugh.
Belgian officials confirmed that one of the suicide bombers who blew themselves up at Brussels airport was a jihadi linked to the Paris attacks.
Secretary of State John Kerry offered a message of solidarity to Belgium in the wake of attacks.
Mason Wells was with a group of Mormon missionaries who were in Brussels during Tuesday's attacks.
Kerry also brushed off criticism that Obama should have rushed back to the U.S. from Cuba after the Brussels bombings occurred.
The Brussels bombers used this top-floor apartment in the lead-up to the attacks which killed at least 31 people.
A fifth suspect in the Brussels bombings was named in media reports Friday as 28-year-old Naim al-Hamed.
Sascha and Alexander Pinczowski had just arrived at the Brussels Airport when two explosions went off Tuesday.
Police and troops descended Friday on a Brussels neighborhood where a suspected bomb factory was found earlier this week.
The family of Sascha and Alexander Pinczowski "ask for continued prayers." The siblings just arrived at the airport when the explosions occurred.
Najim left for Syria in 2013 and broke all contact with his family, his brother said Thursday.
Strangers helped strangers, not because it was it was their job but because they saw fellow humans in need.
Privacy rights made Belgium a "safe haven" for ISIS, says official.
"I am an optimist, but I actually think that it may have the reverse effect," Comey said Thursday.
Since the rise of ISIS, numerous terror plots have been thwarted in the U.K., France, Belgium and Germany.
The brothers who attacked the subway and the airport were listed in U.S. terror databases.
The brothers behind this week's Brussels bombings also spied on a top nuclear researcher in the hope of building a so-called "dirty bomb."
Yassin Aanouz suffered physical injuries in the attack on Brussels Airport but is worried about another, deeper scar.
Police in Brussels are searching for the "man in white" who was spotted on surveillance footage at Brussels Airport with two suicide bombers.
At least four Americans and two New Yorkers are still unaccounted for after the Brussels bombings, according to family members.
Officials have not said how many suspects may be involved — perhaps to avoid raising fears of terrorists in the midst.
NBC News' Claudio Lavanga attended the evening ceremony bringing us a firsthand account on the emotions present at the vigil for the victims of terror.
The sources told NBC News that they are certain suspect Najim Laachraoui, 24, died at the Brussels airport Tuesday morning.
"If you have a determined terrorist who is willing to give up their life ... it's almost impossible to prevent that, an expert said.
The terror attacks in Belgium shut down the Brussels airport -- stranding thousands.
European authorities are searching frantically for terrorism suspect Najim Laachraoui amid fears he has escaped authorities' clutches — again.
A confidential U.S. cable shows that Belgian officials thought they were having some success slowing the flow to Syria and tracking returned fighters.
People across the Belgian capital gathered in silence at noon Brussels time to honor the victims of Tuesday's terror attacks.
With key locations still sealed off after Tuesday's terror attacks, one morning commuter struck a defiant note saying terrorists would not dictate the
A glimmer of hope that an American couple was found after more than 24 hours missing in the aftermath of the Brussels attacks faded later Wednesday.
Thousands observed a minute of silence on Wednesday, the first of three official days of mourning for the victims of the Brussels terror attacks.
Chad and Kimberly Wells said their son Mason was lucky to escape serious injury in the Brussels airport bombing. The Mormon missionary suffered lower-
People around the world are expressing their support for Belgium by sharing pictures of beloved cartoon character Tintin crying.
Two brothers were identified as the suicide bombers behind the Brussels terror attacks on Wednesday.
Many countries showed their solidarity with Belgium in the aftermath of the Brussels terror attacks.
A massive migration wave has made it all but impossible for countries to monitor who comes and goes in many European countries.
U.S. authorities have beefed up security and Homeland Security Sec. Jeh Johnson is urging people to be on the lookout for suspicious behavior.
NBC's Harry Smith reflects on this tragic day in Brussels, — but even under the threat of terror, the world must still find a way to carry on.
The GOP presidential field Tuesday sparred over the proper response to the Brussels terror attacks.
Within hours of the attacks in Brussels Tuesday morning, artists posted images on social media to express solidarity with the people of Belgium.
King Philippe of Belgium addressed the Belgian nation stating that the 'threat we face will be confronted with fortitude, calm and dignity'.
Belgian police continue raids throughout Brussels for clues and suspects in Tuesday's attack.
The U.S. House of Representatives holds a moment of silence on Tuesday in the wake of the attacks in Brussels.
The situation on the ground in Belgium continues to evolve, but here is what we know for sure.
Some of the presidential candidates used the Brussels attacks as a chance to criticize President Obama.
President Obama was briefed on the Brussels terrorist attacks while on his trip in Cuba on Tuesday.
Democratic presidential candidate Bernie Sanders speaks to the media in Arizona about Tuesday's attacks in Brussels.
World monuments displayed solidarity with Belgians following the terrorist attacks in the Brussels Tuesday morning.
Republican presidential candidate John Kasich reacts to Tuesday's attacks in Brussels.
Three Mormon missionaries based in Paris were badly hurt Tuesday by the blast at Brussels airport, the Church of Jesus Christ of Latter-day Saints confirmed.
ISIS has claimed responsibility for the bombings. The blasts at the airport and subway killed at least 31 people, and a suspect is being sought.
NBC's Tom Costello tells TODAY that veteran firefighters in Brussels say "they have never seen injuries this horrific" after the bombings.
Dazed fliers flee from the terminal after suspected suicide blasts hit Brussels' Zaventem airport.
American Evan Lamos was reading about the explosions at Brussels airport when a blast hit the train ahead of him in the Belgian capital's subway.