Two explosions ripped through Brussels airport and a metro station during rush hour this morning causing several casualties.

Reports say 14 people were killed at the airport and another 20 dead in a separate explosion at Maalbeek metro station.

Lorenzo Vella, a 30-year-old Maltese technical attache' at the Malta Representation was slightly injured at the airport. His pregnant wife, who was with him, was unhurt.

The Malta Foreign Affairs Ministry has set up emergency lines: 8007 2203 / +356 2204 2200.

Prime Minister Joseph Muscat said there were no known threats to Malta but security at critical points had been stepped up as a precaution.

The blasts took place at around 8am near the American Airlines check-in desk at the Brussels Airport departures hall and at  Maalbeek metro station, close to the EU institutions.

All metro stations in the Belgian capital were closed. The EU Commission ordered staff to stay indoors or at home following the blasts. 

The terror attack came as the Belgian capital was on a state of high alert following the arrest of Paris atrocity suspect Salah Abdeslam in the city last week.

Images on social media showed shattered windows and smoke rising from the Brussels departure hall. Video footage shot from an airport car park showed people fleeing in terror.

Footage from inside the building showed a scene of devastation with ceiling tiles strewn across the floor and suitcases abandoned.

Passengers were led onto the tarmac and travellers were urged to stay away from the airport.

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.

Sky News Middle East correspondent Alex Rossi, who was at the airport en route for Tel Aviv, told the channel: "I could feel the buildings move."

According to reports, one of the blasts was caused by a suicide bomber and the other may have been packed in a suitcase. 

Foreign Minister George Vella told Times of Malta he was utterly shocked with the news and expressed solidarity with the victims.

Two officials from the Foreign Ministry have been sent to Brussels airport and a hotline will be set up later today.

Air Malta urged passengers to check its website for updates about this afternoon's scheduled flight to Brussels (see below).

Abdeslam, suspected as a planner in the attacks that killed 130 people in Paris, was arrested on Friday after a four-month manhunt, in the same neighbourhood in Brussels where he grew up.

But the Belgian authorities fear he had accomplices while on the run who are still at large and could pose a threat.

Belgian prosecutor Frederic Van Leeuw told reporters at a news conference in Brussels: "(It's clear) we have a general threat."

Abdeslam, 26, a French citizen who grew up in Brussels' Molenbeek neighbourhood, slipped through police fingers on several occasions, including the day after the attacks.

Belgian prosecutors appealed to the public yesterday for information about a man who allegedly travelled to Hungary last year with Abdeslam.

Najim Laachraoui, 24, is said to have travelled to Syria in February 2013. He was checked by guards at the Austria-Hungary border while driving in a Mercedes with Abdeslam and one other person.

Laachraoui is said to have rented a house under the name of Soufiane Kayal in the Belgian town of Auvelais that was allegedly used as a safe house. Prosecutors said traces of his DNA were found there.

Abdeslam has a court hearing tomorrow. France has requested his extradition but Abdeslam's lawyer says his client will fight the request. 

AIR MALTA FLIGHT TO BRUSSELS 'SUSPENDED'

Air Malta said it had suspended this afternoon's flight to Brussels.  

On an exceptional basis, the airline said it is waiving re-booking fees for its customers booked to and from Brussels until Thursday 24th March.

The airline is also offering passengers the possibility to change destination on these tickets.