Streets in the 'jihadi capital of Europe' have been blocked off as anti-terrorism squads launch a major operation.

Large areas have been cordoned off in the Molenbeek district of Brussels, which is known for being rife with ISIS sympathisers and is not far from the EU headquarters.

A police helicopter has also spotted flying overhead.

Streets in the 'jihadi capital of Europe' have been blocked off as anti-terrorism squads launch a major operation

A spokeswoman for the Brussels prosecutor's office, Ine Van Wymersch, said that four searches were conducted and three people have been detained.

But she added: 'The operation has ended. Nothing was found, no weapons, no explosives.'

She declined to provide more details but said that the three would be questioned on Sunday to establish whether they should be charged or released.

According to Belgian media, masked policemen and armoured cars have been patrolling the streets, while officers have also been using ladders to scale buildings.

The area has been linked to several major terrorist incidents in recent years, including being the home of Salah Abdeslam, who masterminded the 2015 attacks in Paris which killed 130 people.

A huge operation was launched in the wake of the atrocities in the French capital, with several key figures being arrested, including Abdeslam.

Large areas have been cordoned off in the Molenbeek district of Brussels, which is known for being rife with ISIS sympathisers and is not far from the EU headquarters

The operation is actually centred around the same street as where Abdeslam was arrested, the Rue Delaunoy.

The area has been linked to several major terrorist incidents in recent years, including being the home of Salah Abdeslam

Perpetrators of the 2004 Madrid train bombings, the Brussels Airport attack and an attack in on a Jewish museum in the Belgian capital have also resided in Molenbeek.

Historian Pieter Van Ostaeyen tweeted: '#Molenbeek Brussels 4 or more houses searched by police forces. Increased presence of military and police reported #Belgium'

Shortly after the Paris attacks, Mr Van Ostaeyen, an expert on jihad, said there were about 190 Belgian fighters in Syria last month, the majority with ISIS, including 47 women.

Just before the turn of the year, a 14-year-old was arrested with a bag full of explosives and a bottle with "Allahu Akbar" labelling.

The boy, who was not named in reports, was part of a group which worked on a construction yard near to the Brussels-West train station.