Police in Manchester were called to disperse 200 guests at a Bank Holiday street party on Monday.
The gathering, in Barleycroft Street, Moss Side, took place as the UK remains in lockdown during the coronavirus crisis.
As officers from GMP Longsight and Moss Side attended the scene at around 1am, an object was thrown through the back window of a police car, forcing it off the road.
The force said the party was just one of a large number of street parties that took place on the May holiday.
They said: "Bank Holiday Monday kept GMP [Greater Manchester Police] busy with a large amount of street parties including Moss side and Hulme where groups ranged from 20 to over 200 persons present.
"Around 1am the neighbourhood team responded to a large gathering on Barleycroft Street in Moss Side which an object was thrown through the rear window of a police vehicle causing the vehicle to be taken off road.”
Current lockdown rules allow for meeting up with one person from another household outside of homes, while social distancing measures are still in place.
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However, Metropolitan Police chief Cressida Dick admitted earlier this month that officers had no power to enforce restrictions like two-metre distancing.
It was recently revealed that all 44 charges brought under the Coronavirus Act – which allows officers to remove or detain a "suspected infectious person" for screening and assessment – were ruled incorrect, including 13 wrongful convictions.
And 12 charges under the Health Protection Regulations 2020, which give police powers to break up gatherings and fine people breaching restriction of movement rules, were also wrong.