Deadly terrorist attacks in Brussels on Tuesday have prompted Belgium’s national soccer team to cancel its scheduled practice session.

Multiple explosions rocked the Brussels airport and subway system Tuesday morning, forcing a lockdown of the Belgian capital and heightened security across Europe. At least 26 people were reported dead.

The Royal Belgian Football Federation posted an announcement on the Twitter account for its national team, saying “football is not important today,” and that “our thoughts are with the victims.”

Belgium will host Portugal in a friendly match next Tuesday at the King Baudouin Stadium in Brussels. The game is scheduled as a warm-up for both teams ahead of this year’s European Championship.

The Portuguese soccer federation said it was in contact with Belgian authorities about security arrangements for the match.

At least one of the attacks Tuesday was likely the result of a suicide bomber, the Belgian federal prosecutor reported. He classified the attacks as the work of terrorists.

“What we feared has happened,” Prime Minister Charles Michel told reporters. “In this time of tragedy, this black moment for our country, I appeal to everyone to remain calm but also to show solidarity.”

There were two explosions in the departure hall of the city’s Zaventem international airport, according to Michel. There was also an explosion on the rail tracks at the Maelbeek subway station, according to a spokeswoman for Brussels transportation department.

A spokesman for the Brussels Metro said 15 people were killed and 55 injured, 10 very seriously, in the train explosion. Belgian media initially reported at least 13 dead in the airport explosions, but later decreased that to 11, citing information from Belgian Health Minister Maggie de Block, who also said 81 people were injured.

“Prayers & thoughts go to all families and friends of the victims,” Belgium midfielder Axel Witsel posted on his Twitter account.

One international soccer player was at the Zavantem airport when the explosions were reported. Norwich forward Dieumerci Mbokani, who is from Congo, was “unharmed but shaken by the tragic events,” the English club said in a statement.

Mbokani was visiting family in Brussels, where he played for Anderlecht for two seasons until 2013.

There was no immediate claim of responsibility for Tuesday’s attacks, and Michel said there was no immediate evidence linking key Paris suspect Salah Abdeslam to them. The explosions happened four days after Abdeslam, a prime suspect in the Nov. 13 Paris attacks that killed 130 people, was arrested in Brussels.

ESPN FC, ABC News and The Associated Press contributed to this report.