Chelsea supporters were feared to have been involved in trouble in Istanbul on the eve of the club's Champions League match against Galatasaray.
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A source with knowledge of the situation told Press Association Sport that two Chelsea supporters were believed to have been stabbed on Tuesday evening, although it was understood neither required any hospital treatment.
"We are aware of the reports and at this stage we don't have anything more to say,'' a spokesperson told Press Association Sport. "We're in touch with the club and Turkish authorities.''
Chelsea have since announced on Twitter that the club is aware of the incidents and is working to ensure the safety of the fans, while advising travelling supporters to use a designated bus from a stop located in Asker Ocagi Cd [situated to the north of Taksim Square] as the Metro will be 'unsafe' on Wednesday.
The club is aware of 2 incidents involving fans in Istanbul last night & is working with relevant agencies to best ensure safety of all.#CFC— Chelsea FC (@chelseafc) February 26, 2014
Earlier in the evening, a spokeswoman for the Chelsea Supporters' Group expressed surprise at the suggestion of problems facing visiting fans, saying the atmosphere in the city was peaceful.
English fans have been victims of violence in Istanbul before, with Leeds fans Christopher Loftus and Kevin Speight stabbed to death before a UEFA Cup tie in 2000.
The Foreign Office later confirmed it was investigating reports of the incidents which took place around Taksim Square.
"We are looking into reports," said a Foreign Office spokeswoman. "We have had no confirmation of an incident. If confirmed we stand ready to provide consular assistance."