Uefa has opened an investigation into allegations of indecent conduct by four Real Madrid players during their Champions League last-16 win against Atletico Madrid.

Antonio Rudiger, Kylian Mbappe, Vinicius Jr and Dani Ceballos allegedly made gestures towards the home fans after Real Madrid beat their city rivals on penalties to book their place in the quarter-finals.

TV pictures showed German defender Rudiger appearing to make a throat-slitting motion, apparently towards the crowd after the shootout victory, while Mbappe was shown seemingly making a crotch-grabbing gesture.

Spanish media said, external Atletico reported the actions to Uefa last week.

The players could be at risk of suspension but there is no guarantee the case will be heard before their quarter-final with Arsenal. The first leg for that tie is at Emirates Stadium on 8 April and the return leg a week later.

In a statement, Uefa said: "[An] ethics and disciplinary inspector has been appointed to investigate allegations of indecent conduct" made by the four Real Madrid players.

"Further information regarding this matter will be made available in due course."