One of the windows of Real Madrid's team bus was damaged on the way into Anfield for Wednesday's Champions League quarter-final second leg against Liverpool.
Images showed Anfield staff cleaning up the mess after the bus parked up outside the ground for the clash.
The bus transporting the players headed down Anfield Road and past several Reds supporters who had gathered to cheer on their own side ahead of the game, which the Reds head into 3-1 down on aggregate.
It isn't clear what caused the damage to the window, with officials seen mopping up the debris and plastic that had come off the side of the vehicle.
Reds fans cheered the Liverpool team bus as it headed into the ground for the match, which will take place behind closed doors.
Liverpool criticised those responsible for the incident in a statement.
The club said: “We condemn unequivocally the actions that led to Real Madrid’s team bus being damaged during its arrival to Anfield this evening.
"It is totally unacceptable and shameful behaviour of a few individuals.
"We sincerely apologise to our visitors for any distress caused.
"We will work together with Merseyside Police to establish the facts and identify those responsible.”
