Football stadium in Madrid
Football stadium in MadridiStock

The police and security forces in the cities where the Champions League quarterfinals are scheduled to take place on Tuesday and Wednesday have announced a high alert and significant increase in security, following threats by ISIS to carry out attacks in one of the stadiums.

The targeted stadiums are two stadiums in Madrid, one in London and another one in Paris. A media channel that supports ISIS published several photos of the stadiums that will host the games on Tuesday and Wednesday, with a caption threatening an attack. Police in Madrid and Paris have announced that they will increase the level of security ahead of the games, while London police have announced that, "We have an extremely strong policing plan" for tonight's match between Arsenal and Bayern Munich at the Emirates Stadium.

The Ministry of the Interior in Spain announced that although the country's security alert level remains at four out of five, at least 2,000 policemen and additional security forces from all over the country will be deployed in Madrid to help the municipal police patrol the two stadiums, where the matches between Real Madrid and Manchester City are scheduled to take place on Tuesday, and Atlético Madrid against Borussia Dortmund on Wednesday.

European football's governing body, UEFA, said it is aware of the threats, but announced that matches in Madrid, Paris and London would go ahead as planned. "UEFA is aware of alleged terrorist threats that have been made ahead of this week's Champions League matches and maintains close contact with the authorities in the appropriate locations. All matches are planned to go ahead as planned, with appropriate security arrangements in place," a UEFA spokesman said.

The deputy mayor of Madrid, Inmaculada Sanz, tried to calm the fears and said that "these messages are usually actions of propaganda to incite fear. Both the security forces and the intelligence services are investigating any possible threat, but there is nothing that makes us predict a situation of special risk."