Two early morning blasts at Brussels' Zaventem airport left a reported 13 dead, with further casualties expected amid a later explosion at Maelbeek metro station.

Belgium is due to play Portugal in the nation's capital next Wednesday (AEDT) as part of its preparations for Euro 2016 and Marc Wilmots's squad is together for a training camp prior to the match.

But the KNVB confirmed in a statement via its social media channels that training will not take place due to the unfolding events.

The statement, which was posted in Dutch, French and English, read: "Our thoughts are with the victims. Football is not important today. Training cancelled."