Chelsea have appealed for supporters to get in contact with information after claims that local authorities attacked Blues fans outside Camp Nou before their Champions League loss to Barcelona.
On Thursday, video footage emerged online appearing to show Chelsea fans being struck by baton-wielding security staff as they tried to leave the stadium after the game.
"We are aware of reports of incidents outside the ground before the game where a number of Chelsea fans were hurt," Chelsea wrote on social media.
"We ask that our supporters contact us with accounts of their experiences of arrival at the stadium so that we can take this up properly with the authorities."
Under UEFA regulations, the host club is responsible for order and security both inside and outside the stadium, and is liable for "incidents of any kind".