Manchester City have "strongly condemned" the actions of those responsible for damage to the Liverpool team coach on its journey back from the Etihad Stadium on Saturday.
The club said an object was thrown towards the coach in a residential area after City's 4-1 Premier League win.
Greater Manchester Police have launched an investigation after reports of criminal damage.
"Incidents of this kind are totally unacceptable," City said.
The Premier League champions added in a statement: "We strongly condemn the actions of the individual(s) responsible.
"We will fully support Greater Manchester Police's investigation into this incident in any way we can.