Other Democrats have urged Mr Nader to abandon his campaign, convinced that he cost Al Gore the presidency in 2000 by siphoning off the votes of more liberal Americans.

"I intend to get elected pres ident," Mr Kerry told his rival, according to the aide, quoted by Reuters. "I'm working hard at this. I think it's a huge deal for the country to get rid of the people in the White House and I think I have the values to do this."

The aide called the session "very straightforward" and said the two men agreed to meet again. Asked if the senator had requested Mr Nader quit the race, the aide replied: "No." Conversely, Mr Nader neither offered to nor gave any hint if he would, he added.

The four-term Massachusetts senator pointed out that he and Mr Nader had been "together for 30 years" on issues like corporate welfare, consumer issues and abortion rights.

A statement by the Nader camp said corporate welfare, corporate crime and union rights were among the issues discussed. It also said the meeting was designed "to put the focus on the human race not the presidential horse race" and that both men agreed to "continue the dialogue".

"From our perspective, we're going to say the kind of thing that Ralph has already been saying, which is to explain how our second front against George Bush is going to help remove him from power."

But Mr Kerry asked Mr Nader not to judge him by his predecessors.

"I have fought with you. I have been with you on a range of issues and you should judge me by my record in the Senate," he said, according to the aide.

Mr Nader brought up the issue of increasing the number of presidential debates and including more candidates in them, his campaign said.

With the country evenly split, a recent AP-Ipsos poll suggests Mr Nader's running could be decisive, with Mr Bush at 46%, Mr Kerry at 43% and Mr Nader at 7%.

An added concern for Mr Kerry is Mr Nader's anti-war sentiment which has won over some voters, in close fought states.

Separate polling shows that in at least half a dozen swing states Mr Kerry would beat Mr Bush in a two horse-race but lose if Mr Nader is standing.

"If this race is as close as I expect it to be, Nader could get a half, or a third or a fifth of the vote he got last time and be decisive again, as he was in Florida," Charles Cook, a political analyst in Washington, told the Los Angeles Times.

In a sign that Mr Kerry is aware his left flank is exposed, he went to Oregon for one of the last primaries with his former anti-war rival Howard Dean.