BRUSSELS- A suicide bomber blew himself up at Brussels airport on Tuesday killing at least 14 people and a further blast tore through a rush-hour metro train in the capital shortly afterwards, claiming 20 lives, according to public broadcaster VRT.
CNN reported that up to 130 people were also injured in the attacks.
A witness said he heard shouts in Arabic shortly before two blasts struck the packed airport departure lounge. Pictures on social media showed smoke rising from the terminal building through shattered windows and passengers fleeing down a slipway, some still hauling their bags.
All public transport in Brussels was shut down, as it was in London during 2005 militant attacks on the underground that killed 52. A further 225 soldiers were sent into the city and the Belgian Crisis Centre, clearly wary of a further incident, appealed to the population: "Stay where you are".
The blasts at the airport and metro station occurred four days after the arrest in Brussels of a suspected participant in November militant attacks in Paris that killed 130 people. Belgian police had been on alert for any reprisal action.

British Sky News television's Alex Rossi, at the airport, said he heard two "very, very loud explosions".

 "I could feel the building move. There was also dust and smoke as well...I went towards where the explosion came from and there were people coming out looking very dazed and shocked."
Alphonse Youla, 40, who works at the airport, said he heard a man shouting out in Arabic before the first explosion. "Then the glass ceiling of the airport collapsed."
"I helped carry out five people dead, their legs mangled," he said, his hands covered in blood.

The blasts triggered concern across western Europe with Britain and France calling emergency security meetings. The Dutch military strengthened security at airports and borders and Britain stepped up police presence at key locations including transport hubs.
Video showed devastation inside the departure hall with ceiling tiles and glass scattered across the floor. Some passengers emerged from the terminal with blood spattered over their clothes. Others sat wrapped with blankets.
A witness said the blasts occurred at a check-in desk.

Belga news agency cited the fire brigade as saying 14 were killed at the airport, but there was still some uncertainty about casualties.
The metro station hit by the explosion was Maelbeek, close to European Union institutions.
The VRT broadcaster carried a photograph of a metro carriage at a platform with doors and windows completely blown out, its structure deformed and the interior mangled and charred. It said ten were killed in the blast.
A local journalist tweeted a photograph of a person lying covered in blood among smoke outside Maelbeek metro station, on the main Rue de la Loi avenue which connects central Brussels with the EU institutions.
Ambulances were ferrying the wounded away and sirens rang out across the area.
The Foreign Ministry said that one Israeli was lightly injured in the attack, and are checking for more injuries.
United Hatzalah volunteer EMT, Yaakov Yeret was present at the Brussels Airport at the time of the attack. Yeret reported that “At the time of the explosion I was praying at the synagogue in the airport. We felt the explosion. We exited the synagogue in order to see what was happening and we joined the stream of people who were being ushered by the police to exit the terminal."

Shortly after the incident, Brussels Airport said through its Twitter account that it had cancelled flights and diverted all traffic to other travel hubs.
"Don't come to the airport - airport is being evacuated. Avoid the airport area. Flights have been cancelled," the airport said..
Brussels Airport serves over 23 million passengers a year.

In a public statement made on television, Belgium's Prime Minister Charles Michel said Tuesday that "this is what we feared and it's what happened to us."
"This is a dark moment for our nation. We need calm and solidarity,' he added.
British Prime Minister David Cameron, whose country is also on a high security alert, expressed shock over the attack. "We will do everything we can to help."
Salah Abdeslam, the prime surviving suspect for November's Paris attacks on a stadium, cafes and a concert hall, was captured by Belgian police after a shootout on Friday.
Belgium's Interior Minister, Jan Jambon, said on Monday the country was on high alert for a possible revenge attack following the capture of 26-year-old Abdeslam.
"We know that stopping one cell can ... push others into action. We are aware of it in this case," he told public radio.
French investigator Francois Molins told a news conference in Paris on Saturday that Abdeslam, a French citizen born and raised in Brussels, admitted to investigators he had wanted to blow himself up along with others at the Stade de France on the night of the attack claimed by Islamic State; but he later backed out.
For information about those injured in the attack, a hotline has been set up at: 02/753-73-00.
Tovah Lazaroff contributed to this report.