Twin blasts hit Zaventem airport at about 07:00 GMT, with 11 people reported killed.

Another explosion struck Maelbeek metro station near EU headquarters an hour later, leaving about 20 people dead.

The Islamic State (IS) group said it was behind the attacks in a statement issued on the IS-linked Amaq agency.

Belgium has raised its terrorism alert to its highest level. Three days of national mourning have been declared.

Prime Minister Charles Michel called the latest 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".

Two blasts tore through the departures area of Zaventem airport shortly after 08:00 local time (07:00 GMT).

A suicide bomber was "probably" involved, the Belgian prosecutor said.

Eleven people were killed and 81 wounded in the blasts, Belgian Health Minister Maggie de Block said.

Some witnesses reported hearing shots fired and shouts in Arabic before the two explosions.

Others said that people fled the first blast, only to get caught in the second.

A third bomb failed to detonate and was destroyed by the security services

People were running over others that had fallen, I couldn't breathe. I can't believe I'm alive," 15-year-old Antoine told me as he walked with his school friends in a line of hundreds being escorted on foot and by bus to a sports hall, now a makeshift reception centre.

Three hearses passed, heading towards the ruins of the airport departure hall. People sobbed at the sight of them.

Several tourists were asking police what they should do now, where it was safe to go - and when the airport might reopen.

The police were confused too, but offered what little information they had, telling people to head to a reception centre. An officer repeatedly shouted: "Quickly, keep moving, evacuate, this is serious."