Security will be increased for this week’s Champions League games in Europe after a reported threat from the Islamic State group.
Uefa said it was aware of the threats but that games in Madrid, Paris and London would go ahead as planned.
On Tuesday evening Arsenal take on Bayern Munich at the Emirates Stadium, one of those pictured in the online threat. Met Police said they have a robust policing plan in place.
The Al Azaim Foundation, a media channel responsible for spreading messages from the terror group, shared a post threatening an attack on all four of this week's quarter-finals.
This includes the Emirates Stadium and the Santiago Bernabeu - where Man City will take on Real Madrid.
The post - captioned 'kill them all' - also named the Parc des Princes in Paris and the Metropolitano in Madrid - which are both hosting matches on Wednesday.
Deputy Assistant Commissioner Ade Adelekan, overseeing the policing of London, said: “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.
"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.”
An Arsenal spokesperson added: “We work closely with the Metropolitan Police regarding the safety and security of all supporters and staff at Emirates Stadium for all our matches.”
“Our planning for tonight’s fixture is no different and our approach, working together with the Police and UEFA, is proportionate to the current UK threat level.”
French interior minister Gérald Darmanin said there would be "considerably reinforced" security measures in place when PSG play Barcelona in Paris on Wednesday.
Mr Darmanin continued: “I will remind you that only ten days ago, IS shared a picture of the Munich stadium and said action should be taken against sports venues that host football games - although all sports can be targeted.
“Given how important the Champions League is for football, we are of course talking to our partners.”
A spokesman for 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.”
Meanwhile, in Spain, a government minister said they had taken all necessary precautions to avoid any terror attacks.
Luis Enrique, the coach of Paris St Germain who host Barcelona at the Parc des Princes on Wednesday evening, said at his team’s press conference: “I hope it can be controlled and I hope it’s just a threat and that nothing will happen.
“Of course we are concerned.”
PSG player Danilo added: “Security is always important, not just for us as the players, but for everyone, for everyone who loves sport and this game.
“I do think that’s important, but we do have to focus on what we need to do, playing football. There are other people who need to focus on everyone’s safety and security.”
