The Premier League club said on Wednesday they had accepted a 300 million pounds offer from New England Sports Ventures (NESV) but the deal is being complicated because they are facing a legal challenge from their current owners.
Americans Tom Hicks and George Gillett sought on Tuesday to replace two members of the five-man board with their own people in a final bid to retain control.
Hicks and Gillett also confirmed their commitment to selling Liverpool but said the current offer "dramatically" undervalued the club.
"The board has been legally reconstituted and the new board does not approve of this proposed transaction," a spokesman for the owners said.
The proposed deal's price tag of 300 million pounds includes 200 million in writing down all acquisition debt and taking on additional working capital debts and other liabilities.
The club's American owners would also not have been happy to hear that a sale to NESV has the support of Liverpool's major creditors Royal Bank of Scotland (RBS), according to a source familiar with the situation.
Liverpool chairman Martin Broughton said he was disappointed the current owners had "tried everything to prevent the deal from happening" but added the potential new owners were the best people for the job.
An NESV statement said it wanted to "stabilise the club and ultimately return Liverpool FC to its rightful place in English and European football, successfully competing for and winning trophies".
UNPOPULAR OWNERS
Hicks and Gillett bought the Merseyside club in February 2007 for 218.9 million pounds and have been unpopular with fans for burdening it with debt, leaving little money for transfers.
Fans have held many protests calling for their departure, blaming the club's worst start to a season for more than half a century on a lack of new players, but they still struck a note of caution.
"We've heard all these promises before and it amounted to very little," James McKenna, a representative of the Spirit of Shankly supporters group, told Reuters.
Broughton sought to allay such fears, saying NESV wanted to create a 60,000-seater stadium in a "short timetable" - be it a new ground or an expansion of Anfield - and pointed to their track record with the Red Sox.
"NESV's philosophy is all about winning and they have fully demonstrated that at Red Sox," he said, referring to the two World Series the team won in 2004 and 2007 after an 86-year wait. The first title came two years after the takeover by NESV, headed by multi-millionaire John W. Henry.
The Liverpool deal will require Premier League approval, which could come by Friday, but the legal dispute is the main issue.
"The legal battle is critical," said Wyn Grant, professor of football economics at Warwick University. "If the NESV deal doesn't go through RBS may ultimately intervene."
The 18-times English champions have picked up just six points from seven games this season.
