A window on the bus was smashed and the kick-off delayed by 45 minutes as a result of the trouble caused by the fans who were in their thousands as they celebrated their last match in the stadium before they move to their new ground.
West Ham, will now issue life bans to fans found responsible for attacking the Manchester United team coach with flares and dangerous objects before Tuesday's game at Upton Park.
According to captain Wayne Rooney, Louis Van Gaal was attacked and the players 'were scared to death' as a result of the bus attack.
"We are aware that there were some supporters outside the Boleyn Ground who didn't act in an appropriate way," a club statement read.
"It was an extraordinary night full of extraordinary moments in front of extraordinary fans, 99% of whom behaved impeccably and were a credit to the club.We have already had thousands of tweets and emails from fans to say how proud they were to be a part of such a special evening in West Ham's history.
"However, we are aware that there were some supporters outside the Boleyn Ground who didn't act in an appropriate way when the Manchester United team bus was damaged. That was not acceptable and we will work with the police to identify those responsible and ban them for life."
"It wasn't nice, the coach got smashed up," said Manchester United captain Wayne Rooney told Sky Sports. "I'm sure West Ham as a club will be disappointed with what the fans have doneMore photos...