Dana Reeve held a theatre in Columbus, Ohio spellbound as she spoke of husband Christopher, who died two weeks ago and backed Kerry to lift what he said is President George W. Bush's "ban" on embryonic stem-cell research.

"Today is the moment to transform our grief into hope, Chris is a beacon guiding me," Reeve said, as many audience members wiped tears from their eyes.

Reeve pledged to carry on the Superman star's life's work to drive on the stem cell research, which could one day help spinal cord injury victims walk again.

'Keeping our hope alive'

"I am here today because John Kerry, like Christopher Reeve, believes in keeping our hope alive," Reeve said.

"Eleven days ago Chris died and when he died a light went out in my life," said Dana Reeve, as Kerry watched before a speech in the battleground state of Ohio, which analysts say is key to his White House hopes.

"I have been grieving privately the past week and a half. I have been trying to help the children piece together a life without their dad," said Reeve.

"My inclination would be, frankly, to remain private for a good long while, but I came here today in support of John Kerry because this is so important,? said Reeve.

Bush never mentioned by name

Reeve never mentioned Bush by name, but her speech was a clear indictment of his policies, and suggested they were responsible for stealing hope from victims of spinal injuries and other afflictions.

Reeve said, that to the end, her husband's heart "was full of hope and he imagined living in a world where politics would never get in the way of hope".

"I would like to proudly introduce my friend and declare my vote for the next president of the United States, John Kerry,? said Reeve.

Republican Bush, under pressure from religious groups, has offered public financing only for research on already harvested stem cells.

White House rejects claims of Bush cloning 'ban'

But the White House angrily rejects claims Bush has imposed a "ban" saying he is the first president ever to finance any embryonic stem cell research.

Kerry hugged Reeve for several moments after her speech, as the audience gave her a raucous standing ovation, amid loud chants of "Kerry! Kerry! Kerry!"

"That was a moment of a sharing of extraordinary grace, eloquence, passion and love," Kerry said.

"Dana, Chris is here, and we thank you, everybody was sitting there like I was saying 'how is she doing this?'" said Kerry.

Christopher Reeve died on October 10 from heart failure brought on by his symptoms, nine-and-a-half years after he was paralysed after falling from a horse.

Kerry blasted Bush science policies

Kerry lambasted Bush's policies on not just on stem cell research but on science across the board, "he has an extreme political ideology that slows instead of advances science".

"It is wrong to take hope from people," said Kerry, who received a message on his cell phone from Reeve the night before he died, to thank him for raising stem-cell research in his first presidential debate with Bush.

Kerry, who also had US astronaut John Glenn on hand, pledged to wage a John F. Kennedy style crusade for science, likening his pledge to the assassinated former leader's challenge to put Americans on the moon.

"You get the feeling that if George Bush had been president during other periods in American history, he would have sided with the candle lobby against electricity, the buggy-makers against cars and typewriter companies against computers," he joked.

"We will not stand in the way of the future, we will lift President Bush's ban on stem cell research. I'm going to be a president who believes in science."