A statement from the Metropolitan Police has said that two people have sustained minor injuries during an incident outside Upton Park on Tuesday night.
The Manchester United team coach sustained damage as it approached the stadium in East London, with images on social media showing that at least one window on the vehicle had been broken.
It read: "We are aware that a number of items were thrown at the Manchester United coach. One police officer and a member of the public sustained minor injuries. No arrests have been made."
The ground is hosting its final fixture before West Ham United move to the Olympic Stadium next season.