Two men detonated explosives on themselves at Brussels Airport on Tuesday, killing at least ten people, while twenty commuters died in a blast on a metro train near the headquarters of the European Union.

The self-proclaimed Islamic State, a fanatical Islamist group that controls territory in Iraq and Syria, claimed responsibility for both attacks.

Public transport in the Belgian capital was shut down for much of the day, as was international train service to and from London and Paris. Incoming flights were diverted to Brussels Charleroi and Amsterdam Schiphol. Residents of the city were advised to stay indoors.

The lockdown was eased in the early evening when police carried out searches and arrests across Brussels.

“Cowardly”

Prime Minister Charles Michel condemned the attacks as “blind, violent and cowardly” in remarks to the press. “What we had feared has come to pass,” he said.

The government raised its terror alert to the highest level.

King Philippe and his wife, Mathilde, also condemned the “cowardly and heinous” acts and said their thoughts were with the victims, their families and members of the emergency services.

Terror scare

The attacks come only days after Belgian police detained Salah Abdeslam, who was wanted for suspected involvement in the November terrorist attacks in Paris that killed 130.

Brussels itself suffered a terror scare that month when authorities said an attack might be imminent. Sixteen suspects were arrested at the time.

Tuesday’s attacks triggered responses across Western Europe. The Dutch stepped up security at airports and borders, although Prime Minister Mark Rutte said there were no indications an attack was at hand. Britain and France also raised security at their airports. President François Hollande said the attacks struck at “the whole of Europe.”