Belgium Cancel Training Session After Brussels Airport and Metro Attacks

Belgium's national team have cancelled their Tuesday training session following a series of explosions at Brussels Airport and the Maalbeek metro station in the centre of the Belgian city. 

According to French news agency AFP, at least 21 people were killed in the blasts, prompting the Belgium national side to pay their respects:

Tottenham Hotspur's Jan Vertonghen tweeted about the tragedy:

Belgium are scheduled to play a friendly match against Portugal in Brussels on March 29.

Their last scheduled friendly, against Spain back in November, was cancelled in the wake of the coordinated Paris terror attacks that saw 130 people killed, per the Guardian.

One of the main suspects in those attacks, Belgian-born Salah Abdeslam, was arrested in Brussels last week, per BBC News.

Norwich City's Dieumerci Mbokani was at the airport at the time of the explosions on Tuesday and was confirmed to be "unharmed but shaken" in a statement from the East Anglia club.

Belgium and Manchester United winger Adnan Januzaj posted a message of shock and support on Twitter:

Per BBC News, two explosions occurred soon after 8 a.m. local time at Brussels' Zaventem airport, and the metro station was hit an hour later.

The terror threat in the country has been raised to its highest possible level, per CNN:

The match with Portugal is part of Belgium's preparations for the summer's Euro 2016 tournament in France.

However, thoughts of the game and the summer will likely be far from the Belgium players' minds after the tragic events on Tuesday in the nation's capital.