SBOBET Liverpool are investigating allegations of maltreatment from police and stewards at their Champions League clash with Sevilla on Tuesday.
Reds fans were "refused entry, assaulted and treated very poorly", fan group Spirit of Shankly's chairman Jay McKenna told the Liverpool Echo newspaper.
A number of other supporters also tweeted their unhappiness at the conduct of police as well as accounts of fans being denied entrance to the ground for the 3-3 draw.
Liverpool confirmed on Wednesday: "Following detailed and troubling accounts given by Liverpool supporters attending the match against Sevilla last night, the club is seeking to establish the facts regarding their treatment at the hands of the host stewards and local police force.
Jurgen Klopp clapped the Liverpool fans after his side let a 3-0 lead slip to draw 3-3 SBOBET
"The safety and security of our supporters is our paramount concern and we intend to gather all the relevant information before responding further."
UEFA has subsequently told Sky Sports News: "We are aware that there were some issues at the away supporters entrances in regards to fans accessing the stadium. We have no further comment to make at this stage."
Jordan Henderson and Alex Oxlade-Chamberlain applauded Liverpool fans after Sevilla draw
Jurgen Klopp's side let a 3-0 lead slip in their fifth Group E tie, meaning they top the group but must secure at least a draw from their final game against Spartak Moscow, who could also still qualify for the last 16. SBOBET