Pep Guardiola was sent to the stands by the referee at half-time. Photo: Darren Staples/Reuters

BERLIN – Football's European body UEFA has opened a disciplinary case against Manchester City manager Pep Guardiola on an "improper conduct" charge.

Guardiola was sent to the stands at half-time by Spanish referee Antonio Mateu Lahoz, shortly after City had a goal disallowed for offside in a 2-1 defeat to Liverpool in the Champions League on Tuesday.

Guardiola faces proceedings under two articles of UEFA's disciplinary regulations relating to "dismissal from the bench" and "improper conduct of the coach," a statement said.

Liverpool also face disciplinary proceedings over fan behaviour for the setting off of fireworks and the throwing of objects in the ground.

City went out of the Champions League on a 5-1 aggregate over the two legs of the quarter-final tie.