LONDON, United Kingdom (AFP) — Britain boosted security at its international transport hubs following the deadly attacks in Brussels on Tuesday as Prime Minister David Cameron urged Europe to stand together against the terror threat.

Security was stepped up at ports, borders and airports, though police chiefs and politicians insisted there was no specific intelligence pointing towards an attack in Britain.

One Briton was confirmed injured in the Belgian capital and was receiving treatment, Cameron’s spokeswoman told reporters.

“We’re aware of one British national injured at the airport. We’re now working to provide consular support,” she said.

Cameron chaired a meeting of COBRA, Britain’s emergencies committee which brings together ministers, police and intelligence officers.

“We face a very real terrorist threat right across the different countries of Europe and we have to meet that with everything we have,” he said afterwards, as he announced extra security.

“These are difficult times, these are appalling terrorists but we must stand together to do everything we can to stop them and to make sure that although they attack our way of life and they attack us because of who we are, we will never let them win.”

Britain’s official national threat level from international terrorism was raised in August 2014 to severe, the second highest of five levels, meaning an attack is considered highly likely.

Mark Rowley, Britain’s counter-terror police chief, announced increased patrols.

“As a precaution, forces across the UK have increased policing presence at key locations, including transport hubs, to protect the public and provide reassurance,” he said.

“This is not in relation to any specific information or intelligence,” he added.

Rowley said that in London, extra police were being mobilised to conduct “highly visible patrols at key locations”, including on the transport network.

Some 52 innocent people were killed in the July 2005 Islamist suicide attacks on London’s transport system.

“We urge the public and businesses to be alert but not alarmed and report anything suspicious,” Rowley said.

Detectives appealed for any British nationals or media with footage of the attacks to assist the investigation by uploading images or video to an online platform.

British police expertise was being offered to Belgian colleagues, Cameron’s spokeswoman said.

“This is a shared threat that we should be working together to tackle,” she said.

Security was increased at Britain’s border control in Calais, northeastern France, and at the seaport of Dover across the Channel.

It was also increased at London’s Saint Pancras international rail station. Eurostar passenger trains between the terminal and Brussels were suspended.

London Gatwick, the country’s second-biggest airport, confirmed it had boosted security patrols.

London Heathrow, Europe’s busiest airport, said police were providing “a high visibility presence”.

The Foreign Office warned British nationals in Belgium: “You should remain alert and vigilant, stay away from crowded places and avoid public transport.”