Nottingham Forest say Steve Cooper remains manager but “results and performances must improve immediately”.
In a statement, owner Evangelos Marinakis said he wished to end “false and disruptive reporting” about Cooper’s future.
Forest have not won in eight games, the longest winless run in the top flight.
Cooper joined Forest in September 2021 and guided them to the Premier League for the first time since 1999 in his first season.
He has signed 29 players since last summer, spending more than £160m.
Marinakis said: “No-one denies that our club is in a difficult position in the Premier League.
“But we wish to end the speculation and the false and disruptive reporting in the media to confirm that Steve Cooper remains our manager at Nottingham Forest.
“We have all been disappointed with recent performances and it is very clear that a lot of hard work needs to be done to address this urgently.”
Cooper signed a new contract at the City Ground until 2025 in October, when the club were bottom of the table after eight games.
Marinakis said “there can be no time for distractions, rumours and speculation” and that Cooper and his players need “hard work, determination, a commitment”.
Asked about his position following the defeat at Elland Road, Cooper said he had “trained” himself to “focus on the stuff I can control”.
He said: “I always think of the greater good of the football club.
“Any sort of worry, disappointment or frustration I’m feeling right now is the fact that Forest have lost a game they could have done so much better in.”
Analysis
BBC Sport’s Simon Stone
In clarifying Cooper’s position, Forest’s owner could not make it any clearer: “Results and performances must improve immediately.”
Marinakis didn’t have to be so blunt. It is clear Forest need a form reversal.
If Forest lose their Midlands derby at in-form Aston Villa on Saturday, they will be in the bottom three as the two sides immediately below them – Leicester and Bournemouth – meet at the King Power.
Given Marinakis’ words, the pressure will be back on Cooper again and all eyes will be on the owner to see how he reacts.
Cooper retains the backing of the vast majority of Forest fans, but is equally clear Marinakis’ patience is wearing thin.
He has helped his manager by quietening the noise building up around him following the defeat at Leeds.
Now Cooper and his team simply have to deliver.
