Middlesbrough have confirmed the departure of head coach Aitor Karanka.
The news brings to an end his three-and-a-half year tenure, having joined the club in November 2013.
Karanka guided Middlesbrough to promotion last summer as they finished second in the Championship, a year after narrowly missing out by losing in the playoff final to Norwich.
However, his team have struggled in the Premier League this season, currently sitting 19th with just four wins from 27 games. Their last league win came against Swansea on December 17.
He had remained confident of easing Boro back to safety in the remaining 11 games of the season and was encouraged by his team's display in Saturday's 2-0 FA Cup quarter-final defeat by Manchester City.
However, he did not get the chance as his reign came to an end after three years and four months.
A statement on the club website read: "Middlesbrough Football Club can today confirm the departure of Head Coach Aitor Karanka. Following discussions, both parties have agreed that it is in the best interests of the club to make this change.
"The club would like to thank Aitor for all his hard work over the past three-and-a-half years and for the success we've had during that time. We wish him all the best for the future.
"Aitor Karanka said: "I'd like to thank Middlesbrough for a wonderful opportunity and the players, staff and all the people at the club who I have worked with. I'd also like to thank the fans for their support. This club will always hold a special place for me and I wish everyone connected with Middlesbrough Football Club the very best for the future."
"Steve Agnew will step up from his role as assistant Head Coach to take control of first team affairs with immediate effect."
Karanka tweeted these messages shortly after his departure was announced:
I'd also like to thank the fans for their support. This club will always hold a special place for me. 2/3— Aitor Karanka (@Karanka) March 16, 2017
I wish everyone connected with Middlesbrough Football Club the very best for the future. Up The Boro! 3/3— Aitor Karanka (@Karanka) March 16, 2017
Middlesbrough are the Premier League's lowest goal-scorers this season, with just 19 in 27 games, while they have also had the fewest shots and won fewer games than any other team.