[Gallery] Aftermath And Photos Of The Suspects Of The Terrorist Attack At Brussels Airport And Metro

Bombs exploded Tuesday at the Brussels airport and in the city's subway, killing at least 31 people and wounding dozens, as a European capital was again locked down amid heightened security threats. The Islamic State group claimed responsibility for the attacks.



The two airport blasts, at least one of them blamed on a suicide bomber, left behind a chaotic scene of splattered blood in the departure lounge as windows were blown out, ceilings collapsed and travelers streamed out of the smoky building.



About an hour later, another bomb exploded on a rush-hour subway train near the European Union headquarters. Terrified passengers had to evacuate through darkened tunnels to safety.



"What we feared has happened," Belgian Prime Minister Charles Michel said. "In this time of tragedy, this black moment for our country, I appeal to everyone to remain calm but also to show solidarity."



Belgium raised its terror alert to the highest level, diverting planes and trains and ordering people to stay where they were for most of the workday.



Authorities also released a photo taken from closed-circuit TV of three men pushing luggage carts, saying two of them apparently were the suicide bombers and that the third - dressed in a light-colored coat, black hat and glasses - was at large. They urged the public to contact them if they recognized him.



Police later conducted raids in Brussels searching for one of the suspects, and found a nail-filled bomb, chemical products and an Islamic State flag in the search of a house in the Schaerbeek neighborhood, the state prosecutors' office said in a statement.