The kick off to West Ham United's final match at their Upton Park ground was delayed by 45 minutes, from its original start time of 7.45pm to 8.30pm, after fans from the east London club targeted the team coach of opponents Manchester United outside the ground on Tuesday (10 May).
Thousands of fans were on the streets next to the Boleyn Ground, but things turned violent when the Hammers' supporters targeted the visitors' coach as it drove onto Green Street. Video footage showed objects, including smoke bombs, being thrown with pieces falling off the side of the coach, with the Manchester United players refusing to alight the coach into the street.
A police officer and a member of the public suffered minor injuries, a spokesman for Scotland Yard said, adding that no-one had been arrested, before adding: "An appropriate policing plan is in place."
Manchester United captain Wayne Rooney told Sky Sports: "It wasn't nice, obviously the coach was smashed up but we're here now.
"'I'm, sure you'll see the images so it's not for me to say but obviously it was disappointing. It's a big night for West Ham with leaving the stadium but I'm sure they'll be disappointed with what the fans have done."
Meanwhile West Ham co-owner, David Sullivan, said he regretted the incident but believes United ought to have arrived at the ground earlier: "Man United should have got here at 4pm, they know it's our last game" he said. "The same thing happened to them at Tottenham a few weeks ago.
"I'm gravely disappointed. More for our supporters who have got trains to get home. We have a wonderful show after the game and many can't stay."
In a statement, the FA said: "We will work closely with both clubs and the Metropolitan Police to fully investigate these matters."
The visit of United is the 2,164th and very final game to be held at the club's famous old ground, before it moves to the Olympic Stadium in the summer break ready for the Premier League 2016/17 season.