Democratic challenger John Kerry refused to concede defeat to George W. Bush in the key swing state of Ohio, throwing television projections on Tuesday's hotly contested US presidential election into question.

The Kerry campaign rejected predictions by two networks ? Fox and NBC ? that called the midwestern state for Bush, saying that more than 250 000 ballots had not yet been counted and the president's only led by 100 000 votes.

"The vote count in Ohio has not been completed," Kerry campaign manager Mary Beth Cahill said in a statement. "We believe when (it has), John Kerry will win Ohio."

Her comments left open the possibility of a re-run of the legal challenges to the 2000 election in Florida which Bush eventually won by only 537 votes after the US Supreme Court ordered a halt to recounts.

The projections by Fox and NBC ? which were not repeated by the three other major networks ABC, CBS and CNN ? thrust Bush to within one electoral vote of winning re-election.

Ohio too close to call ? CNN

CNN reported that Ohio was too close to call with Bush leading Kerry by just over 100 000 votes, or 51 to 49 percent, with 93 percent of the vote counted.

If Bush is determined to have won Ohio, and without results from the seven other states not yet called, the president will be sitting on 269 electoral votes.

The winning candidate needs 270 electoral votes and if the Ohio projections stand, a Bush victory in any one of the other states Hawaii, Iowa, Michigan, Minnesota, Nevada, New Mexico and Wisconsin would put him over the edge

Still, Kerry could tie Bush at 269 votes, forcing the election to be decided by the House of Representatives, if he wins all the 58 electoral votes that those seven states account for.

Tie tantamount to loss for Kerry

However, a tie for Kerry would be tantamount to a loss as Bush's Republican party controls the House.

In terms of the popular vote, Bush led with 51.4 million votes, or 51 percent, to Kerry's 47.8 million votes, or 48 percent, with 83 percent of the country's precincts reporting, according to CNN.

In addition to the contested Ohio call, Bush was projected to win Alabama, Alaska, Arizona, Arkansas, Colorado, Florida, Georgia, Idaho, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Montana, Nebraska, North Carolina, North Dakota, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, West Virginia and Wyoming. The projections showed Kerry taking California, Connecticut, Delaware, Illinois, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Oregon, Pennsylvania, Rhode Island, Vermont, Washington, and the District of Columbia.