Iowa rivals step up the campaign

Howard Dean said he was "in full combat mode"

Democratic presidential candidates have been intensifying efforts to win over Iowa voters as they approach the first hurdle in the race for the White House.

The six men taking part in Monday's state caucuses are spending the weekend in a fierce round of campaigning in their bid to win the party nomination.

Latest polls say the main candidates are in a virtual dead heat, with John Kerry and Howard Dean out in front.

They are closely followed by Dick Gephardt and John Edwards.

Mr Dean continued his campaigning after accepting the endorsement of Carol Moseley Braun on Thursday, when she gave up her own bid.

DEMOCRATIC CONTENDERS Howard Dean John Edwards Dick Gephardt John Kerry Dennis Kucinich Al Sharpton [Joe Lieberman and Wesley Clark are not competing in Iowa] Guide: Candidates and issues

He told a crowd of supporters in Council Bluffs: "Now we're going to see if we can convert this incredible grass-roots effort into votes."

For his part, John Kerry told a packed house in Davenport that he was going to win: "And I'm not talking about Monday, I'm talking about 2 November, 2004. We're going to take the presidency."

Key test

Caucuses are meetings held at venues throughout the state - from public halls to private houses - where grassroots party members elect delegates to the national party convention later this year.

WHAT IS A CAUCUS? Derives from an Indian word meaning meeting Instead of going to the polls and casting a vote, party members attend about 2,000 private meetings across Iowa, hold a debate and declare their preference Participants also elect delegates to communicate their choice to county party conventions, which themselves choose delegates to do the same at state and then national level Critics of the caucus system say it is too laborious Supporters of the system say it encourages grassroots participation Q&A: Iowa caucuses US election glossary

Those delegates will determine the party's presidential and vice-presidential candidates.

Iowa is considered strategic because it is the first state to elect delegates, and therefore enables candidates to build momentum.

Many other states use party elections called primaries - rather than caucuses - to test the candidates' popularity.

A new survey published on Saturday, conducted by pollster John Zogby for Reuters news agency, put Mr Kerry at 22.6%, with Mr Dean narrowly behind at 22.1%.

Mr Gephardt was on 19.1% and Mr Edwards at 17.9%. But with a margin of error of 4.5%, there was no clear leader among the four.

Other polls in the last few days have indicated similar results.

Mr Gephardt made a strong pitch for support for the union vote when he told an audience outside the United Auto Workers' hall in Cedar Rapids of his plans to protect American jobs from what he called unfair foreign trade.

"Let's go. We can win. We can make America a better place," he said.

Meanwhile, Mr Edwards criticised the infighting that he said had characterised much of his rivals' campaigning.

"This campaign is not based on the politics of cynicism. It is based on the politics of hope, of what's possible," he said.