Monday 31 October 2016 11:32, UK
UEFA has contacted the Turkish police and football federation to seek assurances over the safety of Manchester United fans in Istanbul.
United play their latest Europa League match on Thursday night when they face Group A counterparts Fenerbahce.
On Saturday, the US government asked some of its nationals to leave Istanbul, and Turkey, immediately following 'security concerns'.
"Whilst there is no information that the threat to US citizens in Turkey also extends to UK citizens, UEFA has today sought the necessary security guarantees from the Turkish Football Federation and the local public authorities regarding the visit of Manchester United and their supporters to Istanbul," UEFA told Sky Sports News HQ.
"Since the recent military coup and increased terrorist attacks in Turkey, such guarantees have been requested for all UEFA matches organised in Turkey.
"To date all matches have taken place without security incidents. UEFA will continue to monitor the situation and provide advice and support to clubs as required."
Foreign Office advice to Manchester United fans (and all UK nationals) remained unchanged on Monday morning - "You should remain vigilant and monitor travel advice. The threat from terrorism remains high."Italian side Napoli are also in Istanbul for their Champions League Group B encounter with Besiktas on Tuesday.