U.S. President Barack Obama condemned deadly terrorist attacks in Brussels on Tuesday, calling for global unity against terrorism and pledging to do everything to help bring those responsible to justice.

A series of blasts rocked the Brussels airport and a metro station in the city, killing at least 34 people and injuring more than 200 others. The attacks came days after a suspect in last year's Paris terrorist bombings was arrested in the Belgian capital.

"We stand in solidarity with them (the Belgians) in condemning these outrageous attacks against innocent people. We will do whatever is necessary to support our friend and ally, Belgium, in bringing to justice those who are responsible," Obama said in a speech during a visit to Cuba.

"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.

Obama also had a phone call with Belgian Prime Minister Charles Michel, during which he offered his condolences, reaffirmed the steadfast U.S. support for Belgium and offered any assistance necessary in investigating the attacks and bringing those responsible to justice, the White House said in a statement.

"The president reiterated that the United States stands together with the people of Belgium, as well as NATO and the European Union, and once again pledged the full cooperation and support of the United States in our shared commitment to defeat the scourge of terrorism," the White House said.

U.S. Secretary of State John Kerry also issued a statement condemning the attacks as "an assault against the Belgian people and the very heart of Europe."

"We stand ready to provide whatever support the Belgian government may require," Kerry said in the statement. "The United States stands firmly with our ally Belgium and with all of Europe in the face of this tragedy. Attacks like these only deepen our shared resolve to defeat terrorism around the world."

Kerry also spoke by phone with Belgian Foreign Minister Didier Reynders.

The two top diplomats agreed that the perpetrators must be brought to justice and that attacks such as these underscored the need for a continued and concerted push by all nations to counter violent extremism, the department said in a statement. (Yonhap)