London - West Ham face a Football Association probe after the troubled club's owners David Gold and David Sullivan were forced to flee their seats when furious fans ran riot during shameful scenes at the London Stadium.
Several West Ham supporters invaded the pitch during Saturday's 3-0 Premier League defeat against Burnley, while hundreds of fans gathered beneath the directors' box to protest against Gold and Sullivan.
Fans made throat-slitting gestures while missiles were seen to be thrown in the direction of the executive seats amid chants of "sack the board" and "you killed our club".
On the pitch, the toxic atmosphere boiled over after West Ham captain Mark Noble grappled one fan to the floor and team-mate James Collins marched two others away.
Burnley's coaching staff let children shelter in their dug-out to avoid being caught in the chaos that left police investigating two allegations of assault.
West Ham said an emergency meeting had been called with all London Stadium stakeholders, which includes Gold and Sullivan, whose decision to uproot the club from Upton Park to Stratford has caused resentment.
The FA is also set to launch a probe, with a spokesman saying: "The FA strongly condemns the crowd disturbances seen today at West Ham United versus Burnley and will be seeking observations from West Ham as well as awaiting the match referee's report."
The east London club, currently just three points above the relegation zone, could be hit with a heavy fine or even forced to play matches behind closed doors as punishment for the disturbances.
In their own statement the Premier League said: "It is essential that everybody who plays or attends a Premier League football match can do so safely.
"There is no place at any level of the game for what happened at the London Stadium.
"While the official investigation of the incidents will be carried out by the Football Association, we will be asking our own questions of West Ham United about what happened this afternoon, especially to ensure similar events never reoccur."
West Ham manager David Moyes admitted he understood why tempers had frayed, but the Scot condemned the ugly scenes.
"As a supporter you can't cross the line. You can't come on the pitch. That's the rule," Moyes said.
"What we need is the club, supporters, players, everyone, is to pull together."
Noble's ascent from boyhood West Ham fan to key player for the club had made him a favourite of the Hammers support.
But even the east London-born star admitted the situation was out of control.
"I'm a West Ham fan and I've always protected the club. But if someone approaches me, I'll protect myself," he said of his clash with the fan.
"It's been like this for the past two seasons, since we moved to this stadium.
"Every time we lose we and the board get a lot of stick. It seemed today that the fans had had enough.
"The atmosphere was horrible. We know a lot of it isn't aimed at the players, but we have to be man enough to play in that atmosphere."
It was an horrific end to a turbulent week which saw a protest march called off as fans' groups turned on each other during threats of violents by one Hammers supporters' organisation linked to the club's notorious Inter City Firm hooligans of the 1970s and 1980s.
Burnley manager Sean Dyche was relieved the poisonous atmosphere didn't end in his players suffering harm.
"When we scored the second the atmosphere changed," he said.
"We know people can't come on the pitch but I can't imagine it was dangerous for the players.
"Hopefully there are better times ahead for West Ham."