Kerry under pressure over claims of affair

Presidential hopeful John Kerry is facing growing pressure to answer allegations that he had an affair with a journalist intern.

Supporters of the Democratic frontrunner say he is the victim of a "dirty tricks" campaign after reports that he tried to cover up the relationship when the claims were revealed on a website.

The woman was today named as 37-year-old journalist Alex Polier who has left the US and is now believed to be in London. Mr Kerry is said to have had an affair with her when she was a young intern working for news agency Associated Press.

After a day of lying low in Washington, the 61-year-old senator is expected to tackle the rumours at a series of media appearances today. His officials have refused to comment in public on the claims, which surfaced on the conservative Drudge Report website, run by the tipster who first reported Bill Clinton's affair with Monica Lewinsky.

But they are said to be furious at what they see as a Right-wing smear campaign against the man likely to face President Bush as the Democratic candidate in November.

The allegations are that Senator Kerry, whose wife Teresa is a member of the wealthy Heinz family, had been involved with a young intern working at a major news organisation.

The intern was said to have fled America at the urging of Mr Kerry after a friend approached a reporter with "fantastic stories". The Drudge Report claimed two of Mr Kerry's rivals for the Democrat nominations knew of the allegations. It said General Wesley Clark, who has bowed out of the race, told reporters privately: "Kerry will implode over an intern issue."

The rumours are said to explain why Howard Dean decided to stay in the race despite trailing badly in the polls. In what will be seen as an attempt to rebuff the allegations, General Clark's campaign team has said he will publicly endorse Mr Kerry today.

The presidential race has become mired in smears this week, with the White House forced to deny reports President Bush failed to turn up for part of his military service in the Seventies. And two days ago a photograph appeared showing Mr Kerry, a decorated Vietnam veteran, with actress Jane Fonda at a 1970 anti-war rally.

After winning 11 out of 13 primaries, Mr Kerry had looked certain to become the Democratic candidate. He faces a test next month when most of the big states, including New York and California, vote to pick delegates for the Democratic convention in July. Few Americans are aware of the affair claims. Newspapers have made no reference to the story, which is largely restricted to internet chatrooms and Right-wing radio talkshows. But the Drudge Report says it is being investigated by Time magazine, the Washington Post and the ABC network.

It is unclear how the allegations will affect Mr Kerry's wife, who is now seen as an asset to her husband's campaign despite revealing that she uses Botox.

Mrs Heinz Kerry, 65, who has an inheritance of more than £300million, was born in Mozambique when it was a colony. She spent her early years as the pampered daughter of a Portuguese doctor but joined the anti-apartheid movement at university in South Africa.

Her first husband, Republican senator John Heinz III, died in a plane crash in 1991. The following year she met the recently divorced Senator Kerry at the Earth Summit in Rio.

A devout Catholic, she is said to have been moved after hearing him recite a Latin prayer in a mass. She recently joked she would "maim" her husband if she caught him having an affair.