Police are investigating crowd disorder after two arrests were made following Manchester City's controversial FA Cup defeat at Wigan yesterday.
Wigan are also to carry out their own "full investigation" after thousands of supporters spilled onto the pitch following the final whistle, with one becoming involved in a physical altercation with City striker Sergio Aguero.
TV footage of the chaos at the DW Stadium appeared to show Aguero raising his arm to push away the fan and later having to be restrained. It is understood Aguero claims he was spat at.
A number of fans also headed towards the end where City fans were sat to continue their celebrations, sparking further disturbances. Advertising hoardings were ripped out and thrown onto the field along with other objects, while missiles were thrown from the field into the stand. There were also clashes between fans and police and stewards.
Police acted to restore order but two arrests were made on suspicion of affray following an incident outside the ground.
"Football is a family event and the disruption that players and fans alike faced last night will not be tolerated," chief superintendent Stuart Ellison of Greater Manchester Police said.
Police added in a statement that no injuries had been reported.
City have not commented but it is understood the club consider what occurred unacceptable, particularly as the safety of players was potentially endangered. The club plan to speak to Wigan over the matter.
Wigan, for their part, have been quick to launch their own inquiries.
"We were disappointed with the action of a minority of supporters who acted in an inappropriate manner," chief executive Jonathan Jackson said.
"Player and staff safety is of paramount importance and we will conduct a full investigation."
England's Football Association is assessing what occurred and will take into consideration the report of referee Anthony Taylor and video footage before considering whether to open its own investigation.
The governing body could also look into a confrontation between City manager Pep Guardiola and his Wigan counterpart Paul Cook. The pair exchanged heated words after City's Fabian Delph was sent off late in the first half.
League One Wigan beat the runaway Premier League leaders 1-0 with a 79th-minute strike from Will Grigg.