Rafael Benitez says he wanted to stay at Newcastle United but could not agree on a shared vision with "those at the top of the club".

After he was unable to stave off relegation from the Premier League in 2015-16, Benitez led the Magpies out of the Championship at the first attempt and subsequently re-established them as a top-flight club.

But Benitez had a difficult relationship with controversial owner Mike Ashley, regularly hinting in his comments to the media at disagreements over the club's perceived lack of transfer activity.

And in a letter to Newcastle fans posted on social media on Monday, the day after his contract expired, Benitez explained why he was unable to agree a new deal for the 2019-20 campaign.

"I wanted to stay, but I didn't just want to sign an extended contract, I wanted to be part of a project," Benitez said.

"Unfortunately, it became increasingly clear to me that those at the top of the club did not share the same vision.

"I'm very sad about that, but I do not regret for one moment my decision to come to Tyneside and I'm very proud about what we achieved together.

"I will always have you in my heart. Best of luck for the future."

Newcastle legend Alan Shearer blasted the club as a "shambles" for allowing Benitez, who won the Champions League with Liverpool, to leave.

"A world class manager. A manager who performed so well in very difficult circumstances. A manager who understood the fans," he wrote on Twitter.

Newcastle are yet to appoint a replacement for Benitez, with managers including Steve Bruce, Claudio Ranieri, Sean Dyche and Garry Monk among those linked with the vacancy.