Manchester United's American owners have confirmed they could sell the club as they explore "strategic alternatives" to boost its sporting and commercial success.

It comes after Sky's City editor Mark Kleinman exclusively revealed the Glazer family were preparing to announce the news and were already being advised by bankers.

Fans of Manchester United have long campaigned against the club's American owners, who they accuse of a lack of investment and saddling the club with too much debt.

After 17 years in charge, they said on Tuesday that the prospect of selling was now on the table.

A statement said the board of directors was "commencing a process to explore strategic alternatives for the club" which will include "new investment into the club, a sale, or other transactions".

It said stadium and infrastructure redevelopment and expansion of the club's global commercial activities will all be looked at.

Manchester United have struggled to get anywhere near the golden era of Sir Alex Ferguson since he stepped down as manager in 2013.

The club's facilities, current manager Erik ten Hag and the attitude of the Glazer family were also criticised by Cristiano Ronaldo in a recent interview with Piers Morgan.

"The Glazers, they don't care about the club. I mean, professional sport, as you know, Manchester is a marketing club," said the player.

The fallout led to the Portuguese star and Manchester United announcing on Tuesday that he was immediately leaving the club by mutual consent.

Another former United star, Gary Neville, has previously called the Glazers "scavengers" who "need booting out of this football club and booting out of this country".

He made the comments after the club was among those looking to form a breakaway European Super League - an idea lambasted by most of the footballing world.

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Avram Glazer and Joel Glazer, executive co-chairmen and directors, said their review would be "fully focused on serving the best interests of our fans, shareholders, and various stakeholders".

However, the statement cautioned that a sale - or any other deal - is not guaranteed.

A partial sale to new investors, with money being raised to redevelopment Old Trafford, is one potential outcome, says Sky's Mark Kleinman.

Potential buyers could include Sir Jim Ratcliffe, the British billionaire and a long-time fan, having grown up in Manchester.

He said in the summer he would be interested if the club was up for sale, but in October revealed he'd met the Glazers and they "don't want to sell".

Billionaires from around the world would also likely be linked to bids, as would sovereign investors hoping to emulate the takeover at Newcastle United - now owned by Saudi state-backed investors.

There will also be speculation that the Red Knights, a consortium led by former United director and leading economist Lord O'Neill, could revive their interest from 2010.

Manchester United's review comes a few weeks after Liverpool's US owners said they were also open to offers and already had interest from groups looking to buy shares.