Security increased at Champions League games in Paris and Madrid after threat

A communication outlet with links to the jihadist group published calls to attack the stadiums hosting all four matches this week. European football's governing body UEFA immediately said all four first-leg games in Madrid, London and Paris would go ahead despite the threats.

Security was strengthened for Arsenal's match with Bayern Munich at the Emirates Stadium in London on Tuesday and the match, which ended in a 2-2 draw, passed off without incident, and there were no reported incidents in the Spanish capital where Real Madrid drew 3-3 with Manchester City.

French Interior Minister Gerald Darmanin said security would be "considerably reinforced" when Paris Saint-Germain take on Barcelona in their first-leg match at the Parc des Princes on Wednesday.

Darmanin said on Tuesday there had been a "threat publicly expressed by the Islamic State" and that police had "considerably reinforced the security measures".

On Wednesday, French government spokeswoman Prisca Thevenot said there had not been any "concrete threat" to the PSG v Barcelona match. "There is not, and the Interior Minister confirmed this earlier today at the cabinet meeting, a concrete threat but we remain cautious at all times," she said.

The 2015 terror attacks in Paris carried out by IS began at the Stade de France national stadium before other venues in the city were attacked, with the loss of 130 lives.

Tight security in Madrid

The second Champions League game this week in Madrid takes place on Wednesday evening, when Atletico Madrid play Borussia Dortmund at the Metropolitano stadium. Pilar Alegria, speaking for the Spanish government on Tuesday, said more than 2,000 police would be deployed for the two games in the capital.

"We are going to have an exceptional deployment of security services, in line with the level of alert set out by the intelligence services," Francisco Martin Aguirre, the government's delegate for Madrid, said in a video message.

UEFA said on Tuesday it was "closely liaising with the authorities at the respective venues" but that all the matches would be played. All matches are planned to go ahead as scheduled with appropriate security arrangements in place."

The pro-IS channel that published the calls for violent attacks featured images of the Emirates Stadium, the Bernabeu and Metropolitano stadiums in Madrid, as well as the Parc des Princes in Paris.

A French expert on the online communication of jihadist groups told 'AFP' they came from Al-Azaim, a mouthpiece for Islamic State's branch in Afghanistan (ISKP), which is suspected of being behind an attack on a concert venue in Moscow last month which killed more than 140 people.

However the expert, who was speaking on condition of anonymity, said the posts were aimed at inciting others, rather than detailing a specific attack. Many European countries are on their highest possible terror warning level after the attack in Moscow.