Qatari banker Sheikh Jassim bin Hamad Al Thani has made an improved bid to secure Manchester United from the Glazer family, a source close to the bid told AFP on Tuesday.

Sheikh Jassim is in a bidding war with British billionaire Jim Ratcliffe after the pair emerged as the main contenders to buy the Premier League giants.

Ratcliffe appeared to be the front runner when a third round of bidding closed last month.

INEOS chemical company founder Ratcliffe, a boyhood United fan, had reportedly placed a higher valuation on the club as he seeks a majority stake.

However, his bid could allow for executive co-chairmen Avram and Joel Glazer to remain invested in the Red Devils - a move that would be deeply unpopular with supporters.

By contrast, Sheikh Jassim's bid is for 100 percent control of the club and promises to wipe United's £970 million ($1.2 billion) debt.

The Glazers, who have failed to win over the fans since they saddled the club with debt in a £790 million leveraged takeover in 2005, appeared ready to cash out at an enormous profit when they first invited external investment in November.

However, they are reportedly holding out for a world record £6 billion fee for a football club before they agree to sell.

The Manchester United Supporters' Trust (MUST) has called for a swift conclusion to the process to allow new owners to be in place for the summer transfer window.

United's fortunes on the field have slumped during the Glazers' reign in charge.

They have not won a Premier League title since former manager Alex Ferguson retired a decade ago.

But United did end a six-year trophy drought earlier this season when they lifted the League Cup in Erik ten Hag's first year as manager.

kca/nr