"Everyone at United remains focused on continuing the team's progress under Ten Hag and working together to deliver success on the pitch."

Last month, Ten Hag said Ronaldo had refused to come on as a substitute against Premier League rivals Tottenham Hotspur, when the forward walked down the tunnel with a few minutes of the game remaining after being put on the bench.

The 37-year-old was then not part of the squad that faced Chelsea the following Saturday before returning to the fold.

Ronaldo later said in the interview he regretted leaving early against Spurs but added his decision to walk off came because he felt "provoked" by Ten Hag.

Ronaldo said in a statement on Tuesday that he loved the club and the fans.

"... That will never ever change," he added. "However, it feels like the right time for me to seek a new challenge. I wish the team every success for the remainder of the season and for the future."

Raphael Varane, Ronaldo's French teammate at United, said last week that the Portuguese's comments had affected the club's players – many of whom are also at the World Cup in Qatar.

Ronaldo confirmed on Monday that an awkward handshake between him and midfielder Bruno Fernandes that was caught on camera and went viral was the result of a joke between the Portugal and United teammates.

He said that he did not believe his actions would affect Portugal's squad, adding that he felt great about the country's chances of winning the World Cup.

Portugal kick off their campaign against Ghana on Thursday. (Reuters)