BRUSSELS, March 22. /TASS/. Over 20 people were killed and 50 injured in explosions that hit the airport and two metro stations in Brussels, BTV TV channel reported on Tuesday.

"According to the sources in the city’s rescue services, over 20 people were killed and 50 injured," the TV channel said.

Medics at Erasme hospital located near the airport told TASS they were receiving people injured in the explosions.

Twin blasts rocked Zaventem, one of Europe’s largest airports, and Maelbeek and Schuman metro stations in downtown Brussels on Tuesday morning.

The airport of Brussels was closed with all flights canceled.

Midi Libre newspaper quoted the royal prosecutor as saying that the airport blast was a suicide attack.

All metro, tram and bus services were shut down in Brussels, according to STIB, the city's public transport operator. Belgium's terror alert level was raised to maximum.

The NATO headquarters and EU institutions in Brussels toughened security measures. The EU Council cancelled all events scheduled for Tuesday.

The offices of Belgium’s prime minister and parliament were evacuated.

Security measures were tightened in Europe’s largest cities and airports, including Moscow, London, Paris, St. Petersburg, Amsterdam and Berlin.