Leeds manager Marcelo Bielsa apologised to Derby's Frank Lampard for spying on a training session.
English Championship leaders Leeds United have apologised to Derby for spying on their training and say they will remind head coach Marcelo Bielsa of his responsibilities.
The build-up to Friday night's 2-0 win over Derby was dominated by claims from the Rams that a man was caught outside their training ground on Thursday.
Derbyshire Police were forced to intervene and it transpired the individual was an employee of Leeds, who was watching a training session.
Bielsa spoke to Derby boss Frank Lampard over the phone to accept full responsibility and was open about the incident when speaking to the media at the match on Friday.
On Saturday morning, Leeds issued a statement, which read: "Following comments made by Marcelo Bielsa yesterday the club will look to work with our head coach and his staff to remind them of the integrity and honesty which are the foundations that Leeds United is built on.
"Our owner Andrea Radrizzani has met with Derby County's owner Mel Morris to formally apologise for Marcelo's actions. We will make no further comment on this matter."