Belgian Prime Minister said Brussels was hit early Tuesday by two "blind, violent and cowardly" attacks on its airport and metro system which left many dead and wounded.

"Two attacks took place this morning in Zaventam airport and Maalbeek metro station, blind, violent, cowardly attacks," Michel announced on national television.

"There are many dead and many wounded, some of them seriously," he said, with the death toll so far put at 21.