US President Barack Obama has condemned the "outrageous" terrorist attacks in Brussels that killed dozens of people.
On Tuesday, at least 34 people lost their lives and more than 200 were injured – many seriously -- in attacks at Brussels international airport and a city metro station in the Belgian capital.
Belgium has raised its terrorism threat to its highest level, and declared three days of national mourning.
Speaking in the Cuban capital Havana, Obama said America would do everything in its power to hunt down those responsible for the attacks.
"We must be together regardless of nationality or race or faith in fighting against the scourge of terrorism. We can and we will defeat those who threaten the safety and security of people all around the world," he said.
"The thoughts and the prayers of the American people are with the people of Belgium and we stand in solidarity with them in condemning these outrageous attacks against innocent people," said Obama.
"We will do whatever is necessary to support our friend and ally Belgium in bringing to justice those who are responsible, and this is yet another reminder that the world must unite."
A series of explosions ripped through Brussels airport, followed by blasts at the metro station in the city on Tuesday at 07:00 GMT.
Belgian broadcaster VRT said at least 14 people were killed after two explosions targeted the departure hall of Zaventem Airport. According to reports, shots were fired right before the blasts.
Shortly after the attacks in the airport, explosions hit Maelbeek metro station near the European Union’s main buildings, leaving at least 20 people dead.
Belgian Prime Minister Charles Michel spoke of "a black time for our country.”
He called the attacks "blind, violent and cowardly," adding: "This is a day of tragedy, a black day... I would like to call on everyone to show calmness and solidarity."