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This week's Champions League fixtures will take place with heightened security measures following alleged threats against the venues from a pro-Islamic State media outlet. UEFA has confirmed that the four matches in Paris, Madrid and London will go ahead as planned on Tuesday and Wednesday.

Government officials in France and Spain have confirmed that there will be an enhanced presence at home matches involving their European representatives while London's Metropolitan Police said "a robust policing plan" was in place for Tuesday's match at the Emirates Stadium. These statements come in light of several posters allegedly published by a media outlet supportive of Islamic State that called for attacks on the quarterfinal matches.

In a statement European football's governing body, said: "UEFA is aware of alleged terrorist threats made towards this week's UEFA Champions League matches and is closely liaising with the authorities at the respective venues. All matches are planned to go ahead as scheduled with appropriate security arrangements in place." 

French interior minister Gerald Darmanin has said there will be a "considerably strengthened" police presence before Paris Saint-Germain's first leg against Barcelona on Wednesday night. "We have seen, among other things, a communication from the Islamic State that particularly targets stadiums. It is not new," he said. 

Speaking at his pre-match press conference, PSG manager Luis Enrique said: "I hope it can be controlled and I hope it's just a threat and that nothing will happen. Of course we are concerned."

In Madrid, where Real Madrid host Manchester City on Tuesday night before Atletico Madrid's tie with Borussia Dortmund 24 hours later, there will be "more than 2,000 police and civil guard officers", confirmed government spokesperson and sports minister Pilar Alegria.

Deputy Assistant Commissioner Ade Adelekan, overseeing the policing of London for Tuesday's match between Arsenal and Bayern Munich, also detailed stepped up measures.

"The UK terrorism threat level remains at 'substantial' meaning an attack is likely, and we work closely with colleagues from across Counter Terrorism Policing in planning for events here in London, to take into account any relevant information that could help us to keep those attending safe.

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"We're aware of online and media reports in relation to calls to target matches across Europe and here in London. However, I want to reassure the public that we have a robust policing plan in place for tonight's match and we continue to work closely alongside the club's security team to ensure that the match passes peacefully.

"As ever, we ask the public to remain vigilant, and if they see any that doesn't look or feel right, then report it to police or security staff."

Holders Manchester City will have nearly 4,000 supporters at the Santiago Bernabeu for their match against Real Madrid. "We're aware of online media reports in relation to calls to target matches across Europe," said Superintendent Helen Caldbeck of Greater Manchester Police's Specialist Operations Branch.

"However, I want to reassure travelling fans that, as we do with each European fixture, we have been working closely alongside our international policing colleagues and security teams from both football clubs to ensure that a robust policing plan is in place and supporters can enjoy the occasion in a safe environment."