Two police officers suffered injuries as Manchester City’s team coach was attacked at Anfield.
Liverpool fans had converged outside the stadium to welcome their side ahead of Wednesday’s Champions League quarter-final first leg tie.
But several objects including flares, bottles and cans were thrown at the City coach from members of the large crowd which had gathered on the route.
Although no members of the Premier League leaders’ travelling party were injured, their vehicle was deemed unsafe to be driven for its return journey.
Paul White, Merseyside Police’s Match Commander Superintendent said: “Thankfully no-one on the bus was injured, but injuries were caused to two of our officers when projectiles were thrown towards the bus.
“The officers and stewards are there to protect the public and keep them safe.
“This behaviour by a number of people who threw bottles, cans and pyrotechnics towards the bus is completely unacceptable and we will conduct enquiries to identify who was responsible and bring them to justice.
“We worked very closely with both clubs to ensure the safety of the public and the teams themselves, and it is disappointing to see that a number of people behaved in this appalling way.”
Speaking after his side’s 3-0 defeat, Pep Guardiola admitted he did not understand why Reds supporters chose to attack their coach.
He said: “Normally when the police know it is going to happen, they tried to avoid it from happening so I did not expect it from the Liverpool side, their people.
“One year ago something happened in Dortmund.
“We come here to play football and I don’t understand this kind of situation.
“The bus is destroyed but I did not expect a prestigious club like Liverpool doing this kind of thing.
“It is not Liverpool, it is the people, maybe one, two or three, but hopefully it does not happen again.”
Liverpool responded to the incident by condemning the actions ‘in the strongest possible terms’ and vowed to identify the perpetrators.
“We apologise unreservedly to Pep Guardiola, his players, staff and officials caught up in the incident,” read a club statement.
“The behaviour of a number of individuals was completely unacceptable and the club will cooperate fully with the authorities to identify those responsible.
“The priority now is to establish the facts and offer Manchester City whatever support is necessary.”