Officers had bottles thrown at them and one was assaulted as police tried to break up an illegal rave at a disused warehouse in Birmingham overnight.
West Midlands Police forced their way into the illegal party in Bordesley Street, Digbeth - seizing a sound system, Class A drugs and a knuckleduster.
Around 150 were found inside the warehouse - breaching coronavirus regulations.
One officer suffered injuries after being assaulted, with a 36-year-old man now in custody for questioning.
A fine of £200 was issued to those in attendance for breaching Covid lockdown measures.
Chief Superintendent Andy Beard said: "It’s extremely disappointing that some are still not grasping that such events only increase the risk of spreading a deadly virus.
"It’s unacceptable when people recklessly ignore the rules and put themselves and others at risk of catching the disease. It’s also unacceptable that officers should be attacked while going about their duties.
"We’ve seized equipment, drugs and a weapon and we’ll be looking to ensure there will be no repeat again."