(CNN) English Premier League club Manchester City has said a fan is in a "critical condition" in hospital after an alleged assault in Germany following the team's Champions League match against Schalke Wednesday.

"The club are working with Greater Manchester Police and German Police to ascertain more information," City said.

"Club staff have remained in Germany to support the family of an injured City fan who is currently in a critical condition in hospital."

Pep Guardiola's side, which beat the Bundesliga outfit 3-2 in the first leg of the last-16 Champions League tie at the Veltins-Arena, asked anyone with information to contact police.

Having gone into the break 2-1 behind, 10-man City recovered against Schalke thanks to late goals from Leroy Sane and Raheem Sterling to take an advantage to the Etihad Stadium for the return leg on March 12.