West Ham have sacked manager Manuel Pellegrini.
The Hammers slipped to their fourth straight home defeat against Leicester on Saturday evening and lie one point above the relegation zone.
A West Ham statement read: "Joint-Chairmen David Sullivan and David Gold, along with the board and everyone at West Ham United, would like to place on record their thanks to Manuel for his service over the past 18 months."
Sullivan said: "It is with great disappointment that we've had to make this decision. Manuel is a gentleman and it has been a real pleasure to work with someone of his calibre.
"However, it has become clear that a change is required to get the club back on track in line with our ambitions this season.
"We felt it was necessary to act now in order to give the new manager as much time as possible to try and achieve that goal."
Pellegrini's expensively assembled side started the season in fine form, but a run of two wins from 14 matches - and four straight home defeats - saw them tumble from fourth to 17th in the space of three months.
The 66-year-old, a Premier League title winner with Manchester City, spoke to the media after the 2-1 defeat to Leicester and admitted he did not know if he would still be in charge against Bournemouth. By 9pm, he had his answer.
David Moyes, who was in charge before Pellegrini, is understood to be among the front-runners to take over, having saved the Hammers from relegation when he replaced Slaven Bilic in November 2017.