Britain’s Foreign Office on Tuesday warned UK fans travelling to Paris for the Euro 2016 soccer tournament to remain “vigilant at all times” as busy areas could be “potential targets for terrorist attacks”, The Independent reports.

The updated advice from the Foreign and Commonwealth Office highlighted stadiums, fan zones and other venues broadcasting the tournament as potential targets for atrocities.

“During Euro 2016, stadiums, fan zones, venues broadcasting the tournament and transport hubs and links represent potential targets for terrorist attacks. You should be vigilant at all times, especially in areas hosting Euro 2016 events, and follow the advice of local French authorities,” the warning said.

British counter-terrorism officers are playing “a key part” in planning against attacks which may target the tournament and a UK intelligence team has travelled to Paris to work with their French counterparts to assess possible threats, according to The Independent.

Commander Dean Haydon, the head of Scotland Yard’s anti-terror squad, said, “As we approach the Euros, any operation such as that in any country is clearly a concern. As you would expect, we are working with the French and other local police and security and intelligence agencies across the world to properly understand is there a threat to the Euros.”

“Certainly we have seen propaganda, ISIS and potential talk of plots against the Euros, but we’re working with all those various different agencies to police and make the Euros a safe event and a safe games,” he added.

“We’re a key part of the planning. Although the ultimate policing of the event and the planning is for the French, we are all involved in properly trying to understand the threat, if there is one.”

Earlier this week, French President Francois Hollande acknowledged there was a threat of an attack during the Euro 2016 soccer championship, but said the country must not be intimidated.

France is on high alert for possible terror strikes during the tournament opening on Friday, following jihadist attacks in Paris in January and November last year.

The British warning comes after Ukrainian police said they had arrested a French terror suspect who was gathering heavy weapons and explosives to target Muslim and Jewish places of worship as well as administrative buildings and infrastructure such as bridges and railways during the competition.

Police said Monday the unnamed man was arrested in late May on the border with Poland carrying 125kg of TNT which he had acquired in the restive eastern Ukrainian province of Donetsk.

In April it was revealed that the Brussels, Belgium bombing cell planned to attack the Euro 2016 soccer cup. 

Prosecutors revealed that the cell – which includes dozens of Islamists, many of whom are related – had not initially chosen Brussels’ airport and metro stations as a target, but had initially planned a mass terror attack in France.