As many as 34 people have been killed and more than 130 wounded in what is thought to be a pair of coordinated suicide attacks at Zaventem Airport and Maalbeek metro station in Brussels today.
Police believe as many as 14 people were killed in two explosions at the airport, which is thought to have taken place near to an American Airlines desk. A further 80 people are thought to have been wounded in the blast. One British national is among those injured.
Belgian media are reporting that a further 20 people were killed in the metro station attack and 55 wounded, 10 critically.
Islamic State has claimed responsibility for both attacks, according to monitoring agency Site Intel Group.
The attacks began just after 8am at Zaventem Airport. Belgian news agency Belga reports that shots were also fired and shouting in Arabic was heard during the incident at the airport.
Belgian police have since found a Kalashnikov assault rifle next to the body of one of the attackers, broadcaster VRT has reported.
Just 90 minutes after the airport attack another explosion occurred at the Maalbeek metro station in central Brussels, near to EU offices. Around 500 flights have been cancelled in and out of the airport, the entire metro network has been shut down and police have shut off the A201 highway near to the airport.
Eurostar has also suspended all services into the country as a result, while Gatwick and Heathrow airports have increased security in the UK.
Jan Jambon, deputy prime minister and minister of security and home affairs, has raised Belgium's terror alert to the highest level.
The airport attacks blew out the windows of the terminal, and images posted on Twitter showed the extent of the damage caused to the building and the walking wounded caught in the explosions.
Insane.. https://t.co/WJvIlsAXXc— Russian Market (@russian_market) March 22, 2016
By the afternoon, people were apparently being kept in a hangar at the airport.
The blasts come four days after the capture in Brussels of Salah Abdeslam, the main suspect in the Paris attacks in November.
British Prime Minister David Cameron is chairing an emergency Cobra meeting today to discuss the UK response to the attacks.
Met Police assistant commissioner Mark Rowley said police forces across the UK have already increased policing presence "at key locations, including transport hubs".
"This is not in relation to any specific information or intelligence," Rowley said in a statement this morning.
"In London specifically, the Metropolitan Police Service has mobilised additional officers, who will carry out highly visible patrols at key locations around the capital, including the transport network."