Claudio Ranieri has been sacked by Leicester City, nine months after leading them to the Premier League title, BBC Sport reports.
The Foxes are one point above the relegation zone with 13 matches left.
“The board reluctantly feels that a change of leadership, while admittedly painful, is necessary in the club’s greatest interest,” read a statement.
Ranieri, 65, guided the Foxes to the title despite them being rated 5,000-1 shots at the start of the campaign.
His departure comes less than 24 hours after a 2-1 defeat at Spanish side Sevilla in the first leg of their Champions League last-16 tie.
The Foxes took the Premier League title by 10 points but have won just five top-flight games this season, and could become the first defending champions to be relegated since 1938.
They have lost their past five league matches and are the only side in the top four English divisions without a league goal in 2017.
“His status as the most successful Leicester City manager of all time is without question,” added the statement.
“However, domestic results in the current campaign have placed the club’s Premier League status under threat.”
Earlier this month, Leicester gave their “unwavering support” to the Italian.
The statement said, “This has been the most difficult decision we have had to make in nearly seven years since King Power took ownership of Leicester City. But we are duty-bound to put the club’s long-term interests above all sense of personal sentiment, no matter how strong that might be.”
Assistant manager Craig Shakespeare and first-team coach Mike Stowell will take charge of the squad until a new manager is appointed.
Ranieri’s compatriots Paolo Benetti and Andrea Azzalin, both key members of his coaching staff, have left the club.
“The board will now begin the recruitment process and will make no further comment until that process is completed,” Leicester added.