A man has been arrested after a police officer suffered facial injuries during a protest outside Old Trafford.
The 25-year-old man, from Prenton, Wirral, is also being held on suspicion of wounding, violent disorder and burglary.
The Premier League match was postponed due to safety concerns, after fans set off flares, broke into Old Trafford and stormed the pitch.
A number of police officers were injured during the demonstration, Greater Manchester Police said.
One officer suffered a "significant slash wound to his face" and required emergency hospital treatment.
Superintendent Caroline Hemingway said: "Following the events at Old Trafford and The Lowry on Sunday, May 2, a full investigation was launched to ensure all culpable parties were identified and face appropriate consequences.
"Although we currently have one male in custody we are continuing to appeal to the public with information or video footage from the day to make contact with police.
"We are aware of multiple people having filmed the disorder, so we urge anyone with footage that is of good quality to upload it the major incident portal or get in touch as a matter of urgency."
Anyone with information or video footage is encouraged to upload it to GMP’s Major Incident Public Portal at mipp.police.uk/operation/06GMP21M13-PO1 or to call police on 0161 856 7573 quoting incident number 955 of 02/05/21.