West Ham United have dismissed head coach Julen Lopetegui after just 20 Premier League matches in charge.
The 58-year-old joined West Ham in July 2024, replacing David Moyes.
He leaves the Hammers in 14th place, seven points above the relegation zone.
A West Ham statement said: "The first half of the 2024/25 season has not aligned with the Club’s ambitions and the Club has therefore taken action in line with its objectives.
"The club can confirm that Assistant Head Coach Pablo Sanz, Head of Performance Oscar Caro, Head Analyst Juan Vicente Peinado, Fitness Coach Borja De Alba and Technical Coach Edu Rubio have also left with immediate effect.
"The Board would like to thank Julen and his staff for their hard work during their time with the Hammers and wish them every success for the future."
Lopetegui is the fifth Premier League manager to leave his role this season, after Erik ten Hag, Steve Cooper, Gary O'Neil and Russell Martin.
Reports in the media suggest former Brighton & Hove Albion and Chelsea head coach Graham Potter is one of the names being considered by West Ham.
West Ham say "the process of appointing a replacement is under way" and that they "will be making no further comment at this time."
West Ham's next five PL fixtures
West Ham were beaten 4-1 at Manchester City on Saturday, their ninth league loss in 2024/25.
They have conceded 39 goals, with only Leicester City (44), Southampton (44) and Wolverhampton Wanderers (42) conceding more.
West Ham are next in action on Friday in the FA Cup when they visit Aston Villa, before hosting Fulham in the Premier League on Tuesday 14 January.