Greater Manchester Police confirmed they had opened an investigation over the incident which took place after City’s 4-1 win at the Etihad Stadium.
No injuries were suffered and the Liverpool bus was able to continue its journey back to Merseyside.
“Manchester City FC have been made aware that Liverpool FC’s coach sustained damage on its return journey,” City said in a statement.
“We understand an object was thrown towards the coach in a residential area.
“Incidents of this kind are totally unacceptable, and we strongly condemn the actions of the individual(s) responsible.”
City also said they were disappointed by chanting from the home fans that made reference to the Hillsborough disaster in 1989, which led to the death of 97 Liverpool fans.
