AZ Alkmaar have issued an apology to West Ham United after a large group of their supporters attacked the away section at the end of Thursday's Europa Conference League semi-final.
Pablo Fornals scored a 94th-minute winner to secure a 1-0 second-leg win for the Hammers at the AFAS Stadion, with David Moyes's side progressing 3-1 on aggregate to their first European final for 47 years.
However, West Ham's celebratory night in the Netherlands was marred by unsavoury scenes after the full-time whistle, as a large gang of hooded AZ ultras stormed into the away end where friends and family of the visiting players were seated.
West Ham players including Michail Antonio, Lucas Paqueta, Aaron Cresswell, Said Benrahma and Flynn Downes feared for the safety of those in the away section and climbed over the advertising boards in an attempt to break up the mass melee.
AZ Alkmaar have since released a public apology to West Ham and intent to cooperate with the police to evaluate the chaotic scenes on what they describe was "a night to reflect on with shame".
A statement from AZ Alkmaar released on Friday read: "While everyone hoped for a historic European match, it turned into a pitch-black evening due to the events occurring at the referee's final whistle.
"It turned into a night to reflect on with shame. Not because of the football game played, but because of the behaviour of some visitors. Unfortunately, we cannot use the word 'supporters' for these people.
"What happened is beyond all bounds. The club again sincerely apologises to West Ham United and the thousands of well-minded AZ supporters who have also been inconvenienced by the misconduct.
"In the coming period AZ will – together with the police, Public Prosecution Service, and Alkmaar's municipality – evaluate exactly what happened, how it could have happened and what needs to be improved from now on.
"It is clear that things need to be improved. Part of the evaluation is a thorough review of all available footage so that appropriate consequences may follow for those responsible for this outrageous behaviour.
"AZ is a civilised club where sportsmanship and norms and values are paramount. The club will do everything possible, together with the authorities involved, to identify these persons and to take appropriate measures."
Sharing his views on the events after the match at a press conference on Friday, Moyes said: "I was disappointed because I felt like it took the attention off the team and what we did.
"There was nothing we could do, or that West Ham as a club could do. Like anyone, if you saw your family members in trouble then you'd go and help out and that was the situation.
"Unfortunately it's taken up a lot of the news and time. But we're not letting it take away from the fact we reached the final, which is a brilliant achievement."
Meanwhile, West Ham's first-team coach Kevin Nolan is keen to see UEFA hand out tough punishments to the Dutch club and their supporters.
"If this was England, there would be lots of sanctions put on us. I hope they put loads of sanctions on the Dutch," Nolan said on BBC Radio 5 Live's Friday Football Social.
"I am disgusted that they would come and go for family which is what they did."
Before taking on Fiorentina in the Europa Conference League final in Prague on June 7, West Ham have two Premier League fixtures to prepare for including Sunday's home encounter with Leeds United.
