World leaders condemned the attacks that hit Zaventem Airport and Maelbeek metro station in Belgian capital Brussels on Tuesday, killing at least 31 people and wounding 187 others.
Belgian Prime Minister Charles Michel spoke of "a black time for our country."
"What we feared has come to pass. Our country has been struck by attacks which are blind, violent and cowardly," he said.
Leaders across the world joined Belgian PM in condemning the attacks and gave messages of solidarity.
US President Barack Obama condemned the attack and said "We must be together regardless of nationality or race or faith in fighting against the scourge of terrorism," during a historic visit to Havana.
Turkish President Recep Tayyip Erdogan strongly condemned the attacks and said there was no difference between terror organisations, whether they were PKK terrorists targeting Ankara or the attackers in the Belgian capital.
"The heinous attacks in Brussels have reiterated that terror cannot be a method of struggle for freedom, and once again underlined the need for common struggle against all types of terror," Erdogan said in a written statement.
Turkish Prime Minister Ahmet Davutoglu condemned the attacks saying “I curse the attacks that took place this morning in Brussels, once again showing the global face of terrorism.”
“I express condolences to the Belgian government and people, and wish to share feelings of solidarity on behalf of our nation,” said Davutoglu whose country has been in a state of mourning due to a series of terror attacks which have claimed the lives of dozens.
UN chief Ban Ki moon condemned the attacks and called them "despicable."
"The despicable attacks today struck at the heart of Belgium and the center of the European Union," said a statement from Ban's office. "The secretary-general hopes those responsible will be swiftly brought to justice."
The European Union's Foreign Policy Chief Federica Mogherini said March 22 was a sad day for Europe after two explosions tore through Brussels airport earlier in the day.
"We are still waiting for more precise news on the dynamics of the attacks in Brussels but it is quite clear that the roots of the pain we are suffering around our region are very much the same and that we are united in not only suffering our victims but also reacting to these acts and preventing radicalisation and violence together," she said.
Speaking at a news conference after an emergency meeting, French Prime Minister Francois Hollande expressed his country’s solidarity with Belgium after the attacks which he described as "cowardly and horrible."
He added that there is a “global threat which requires a global response.”
Another European leader British Prime Minister David Cameron said he was “shocked and concerned” by the events in Brussels and promised his country would do everything to help.
Spanish Foreign Minister José Manuel Garcia-Margallo blamed the attack on DAESH terror group which he called as “a kind of terrorist cancer that is extending all over the world.”
Serbian Prime Minister Aleksandar Vucic sent a telegram of condolences to the Belgian Prime Minister Charles Michel.
“The world is shocked by the terrorist attacks, which threaten all civilised values we strongly advocate. So once again I want to emphasise the importance of joint efforts that we have to put in a determined fight against terrorism," said Vucic.
The secretary general of the Gulf Cooperation Council (GCC), Abdullatif al-Zayani, expressed GCC’s solidarity with Belgium. The bloc comprises Saudi Arabia, Kuwait, Bahrain, Oman, Qatar and the United Arab Emirates.
Japanese Prime Minister Shinzo Abe was also among those condemning the attacks. He said the world must respond to terrorism, without tolerating it.
Pakistan's Foreign Ministry also released a statement in which it condemned the attack in the strongest terms expressing solidarity with the government and the people of Belgium.