UPDATE: Explosions across Brussels leave at least 34 dead

The attacks, condemned as "blind, violent and cowardly" by Belgian Prime Minister Charles Michel, came after the arrest in the city last week of terror mastermind Salah Abdeslam, who plotted November's Paris atrocity from the notorious Molenbeek suburb of Brussels.

Responding to the attacks, French Prime Minister Manuel Valls said "We are at war. In Europe we have been subjected to acts of war for several months."

A suicide bomber struck first near the American Airlines desk at Brussels airport, with local media reporting that shots were fired amid shouting in Arabic.

The explosion on the Metro was near European Union buildings and the US embassy.

As the city went into lockdown:

• Local media said 14 people were killed at the airport

• The Metro explosion killed 15 and injured 55, 10 critically, transport operator STIB said

• Police forces across the UK increased their presence at key locations as a precaution

• Britons in Brussels were advised by the Foreign Office to avoid crowded places and public transport

• One British national injured in the attacks

• David Cameron called a meeting of the Cobra emergency committee and tweeted a message of support, saying: "I am shocked and concerned by the events in Brussels. We will do everything we can to help"

First news of the attacks came when the airport was rocked by a double blast around 7am UK time.

Jef Versele, 40, from Ghent, told the Press Association: "I was on my way to check in and two bombs went off - two explosions.

"I didn't see anything. Everything was coming down. Glassware. It was chaos. It was unbelievable. It was the worst thing."

He added: "People were running away. There were lots of people on the ground. A lot of people are injured."

Daily Echo reporter James Franklin was in Brussels over the weekend and flew from the airport on Sunday.

He said: "The city was clearly in a state of alert in the wake of last week's anti-terrorism raids and arrests.

"There were soldiers at key sites across the city, including the airport, and a lot more police officers than you would otherwise expect to see, while a police helicopter circled an area of the city centre for much of Sunday afternoon.

"It's truly shocking to see what has unfolded at the airport this morning, my thoughts go to those affected."

The first news of the attack came when the airport was rocked by a double blast with reports of up to 10 dead and many more injured.

Jef Versele, 40, from Ghent, Belgium, was at the airport when he heard the two explosions.

"I was on my way to check in and two bombs went off - two explosions," he said.

Mr Versele was two or three storeys above the source of the explosion but he said many people around him were hurt.

"The bomb was coming from downstairs. It was going up through the roof. It was big.

"About 15 windows were just blown out from the entrance hall," he added.

The attack on the Metro came about an hour later.

Evan Lamos tweeted a picture of passengers climbing from his train into the tunnel near Maelbeek station, saying: "We are being evacuated from the back of the Metro.

"Smoke in the tunnel as we evacuate."

The picture was reminiscent of images after the July 7 attacks in London.

Other images showed the injured from the Metro being treated in the street while at the airport people could be seen fleeing in terror in video footage shot from an airport car park.

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

Responding to the attacks, Prime Minister Michel: "A series of additional security measures have been taken at this moment.

"Military reinforcements have been deployed, reinforcement of border controls and specific restrictions on public transport have been put into place at this time.

"I also would like to say that in this tragic and dark moment for our country, more than ever I call everyone to show calm but also solidarity.

"We are faced with a challenge, a difficult challenge, and we have to face this challenge being united, showing solidarity and being together."

Speaking to reporters in Whitehall, Mayor of London Boris Johnson said: "It looks as though there may be one UK casualty, as I'm sure you are aware, though the details of that are very sketchy.

"The most important thing to get across is we know of no reason to think that there is any read across from what's happened in Brussels to events here in this city.

"We have no intelligence to suggest there is any immediate threat, but as a precaution and for the purposes of reassurance, there has been a stepping up of the presence of police at major airports."

Mr Johnson, who had attended the government's Cobra emergency committee meeting, Mr Johnson added: "Of course, there is an armed presence at the underground and major transport hubs as well."

Mr Johnson said Britain "must show maximum possible solidarity with the people of Brussels and Belgium".

Catherine Bearder, MEP for South East England, said: "My team and I are safe but feeling shaken after the horrific events in Brussels this morning.

"My heart goes out to all the victims of these cowardly attacks and their loved ones, as well as all those who rushed to help them.

"In these difficult times, the UK must stand in solidarity with Belgium and offer any assistance we can."

Fellow South East MEP, Conservative Richard Ashworth, said: "Today's atrocities in Brussels are a direct attack on the values, freedom and democracy of all western societies. 

"Our immediate thoughts must be with the families who have lost loved ones and with the many innocent victims whose lives have been so damaged by this vicious attack.

"It is important that western governments stand shoulder to shoulder to confront this evil,  that intelligence agencies work closely together to  counter this threat and that we all realise that an attack in any European city is an attack on us all."