Chelsea have condemned the actions of a number of their supporters after coins and other objects were thrown towards Manchester City players from the home end at Stamford Bridge during Sunday's FA Cup tie.
The Metropolitan Police have confirmed they have arrested a man for throwing a lighter onto the pitch during the fifth-round encounter, and he currently remains in custody pending further enquires.
Sky Sports News HQ also understands the Football Association have launched an investigation into what is a second instance of coin-throwing in two days after West Brom's Chris Brunt was hit below his left eye at Reading's Madejski Stadium on Saturday.
Referee Andre Marriner was seen picking up coins from the pitch at the Matthew Harding (North) end of Chelsea's ground on Sunday and handing them to fourth official Michael Jones after City players celebrated their equaliser.
City scored through youngster David Faupala in the 37th minute, one minute after Diego Costa took the lead for Chelsea, who won the game 5-1.
Chelsea spokesperson Steve Atkins said: "We condemn such idiotic and dangerous behaviour and if we can identify those responsible then we will ban them from Stamford Bridge.
"It's worth noting that it's a criminal offence too and we will support a police prosecution if we can identify, along with the police, those individuals responsible for that behaviour today."
Blues boss Guus Hiddink added: "I can easily say I was not aware but I was aware and I like always to face the facts.
"There were coins thrown to the Manchester City players in their celebration. We condemn it and I condemn it strongly and I think Chelsea will react. Those people, they must not come into stadiums."
On Saturday, Brunt was hit by a coin he claims was thrown by one of his own supporters during the Baggies' 3-1 FA Cup fifth-round defeat at Reading.
Both the FA and Thames Valley Police are investigating the incident, while police are also probing several other moments of disorder and arrested a 37-year-old man for a racially aggravated public order offence.