Reports from Turkey early on Wednesday claimed two travelling fans had been stabbed on the eve of the Champions League tie.
Chelsea did not confirm the nature of the incidents, but a statement released on the club's Twitter account has warned supporters to steer clear of public transport in the run-up to kick-off.
It read: "The club is aware of two incidents involving fans in Istanbul last night and is working with relevant agencies to best ensure safety of all.
"CFC fans in Istanbul reminded it's not safe to use Metro to and from stadium today. Special bus recommended."
A statement from the British Embassy in Turkish capital Ankara read: "We are aware of the reports and at this stage we don't have anything more to say.
"We're in touch with the club and Turkish authorities."