Ten men have been arrested on suspicion of violent disorder after a fight ahead of a Manchester United match.
An “organised large-scale fight” took place the day before Manchester United played FC Twente in September, starting in Lower Broughton in Salford before moving into Manchester city centre, Greater Manchester Police (GMP) said.
The suspects, aged between 20 and 64, are being questioned in police custody.
The force said two separate cannabis farms were also found during raids earlier and a 36-year-old woman has been arrested on suspicion of cultivation.
Ch Supt Colette Rose said: “Organised violence of any kind has no place in Greater Manchester.
“It does not reflect most people who go to events and games without any intention to cause fear or to commit crime.
“With another big fixture coming this weekend, we want to send a strong message and reassurance that our specialised officers will be deployed to ensure you remain safe and peace is maintained, so you can enjoy the game.”