With Europe still recovering from the brutal terrorist attacks in Paris, the Belgian Counter-Terrorism police launched, this Thursday, a vast pre-emptive operation involving searches in more than 10 properties, to dismantle active jihadist cells. Two men were killed in Verviers, a city in the province of Liège, 70 miles away from the capital Brussels. They were part of a trio planning "a large scale attack" and being closely monitored by Belgian authorities ever since entering the country returning from Syria, more than a week ago.

The operation led by the Belgian Federal Police Special Units caught Verviers' population by surprise.

The three men were Belgian citizens and extremely well-armed, opening fire as soon as the police closed in on their building, near the Verviers railway station. Some of the locals described scenes right out of a war film, at the height of rush-hour. Videos posted on the internet show blasts, gunfire and sirens around the building where these Syria returnees were barricaded. By the end, two of the radicals were killed and the third was badly injured and is in custody. No civilians or policemen were injured.

The authorities believe their plan was to carry out an attack against a police station and behead a prominent law enforcement official to post the video online. The Federal Prosecutor, Eric van der Sypt, confirmed, in a press conference, that these men "were extremely well armed" and "on the verge of committing important terror attacks", possibly "within a matter of hours" but the threat has been "neutralised".

The Belgian prime-minister, Charles Michel, announced that "out of prudence" the terror alert level has been raised from two to three (the second-highest level) and authorities are ready to respond to any potential backlashes to this operation.

The city of Verviers, close to the border with Germany, has been struck by an unusual wave of Islamic radicalisation.

The small town with a population of 56.000 has seen at least 6-10 of its inhabitants leave for Syria to join ISIS.

There seems to be no direct link between this cell and the attacks perpetrated by the Kouachi brothers or Ahmed Coulibaly that killed 17 people in Paris, last week, but the authorities are still investigating.

After the Paris attacks, this successful pre-emptive operation will help rebuild some trust in the authorities' capability to monitor and neutralise such threats. It won't stop the pressure on European leaders to come up with a sensible response to the continuing radicalisation of its youth, with the latest figures, from Europol, showing that as many as 5.000 European citizens are still fighting in Syria.