Slaven Bilic has been sacked as West Ham manager.
The Premier League club announced the departure of the Croatian, who was appointed in June 2015 on a three-year contract, on Monday after Saturday's 4-1 loss to Liverpool.
"West Ham United can confirm that Slaven Bilic has today left his position with the club," the Hammers said in a statement.
The club hierarchy "believe a change is now necessary in order for the club to move forward positively and in line with their ambition", the statement added.
Former Everton, Manchester United and Sunderland boss David Moyes is widely expected to replace Bilic at the London Stadium.
The Hammers statement added: "The club's search for a new manager to take West Ham United forward is under way and an announcement regarding Bilic's successor is expected to be made over the coming days."
Bilic's assistants Nikola Jurcevic, Edin Terzic, Julian Dicks and Miljenko Rak have also left the club with immediate effect.