SEATTLE - Democratic rivals Hillary Clinton and Barack Obama slugged it out in a new round of presidential nominating contests Saturday, scrambling for precious delegates and an elusive edge.

Four states were holding primaries or caucuses for Democratic and Republican contenders with attention focusing on the duel between Clinton and Obama after Super Tuesday saw the two senators finish with honors even.

Democratic caucuses in the northwest state of Washington offered the biggest prize -- 78 delegates to the party's national convention -- out of around 200 up for grabs over the weekend.

Clinton and Obama campaigned fiercely in the state on Friday, with former first lady Clinton promoting her universal health care plan and Obama pushing his message of change in his bid to be the first black US president. Clinton would be the first woman US head of state.

Obama, who according to a SurveyUSA poll leads Clinton by 50 to 45 percent in Washington, attracted a crowd of around 20,000 to a Seattle rally on Friday.

Washington state Democratic leaders said they expected a turnout of between 150,000 and 200,000 voters, up from usual levels of around 100,000.

Early Republican results from the party's Kansas caucuses on Saturday boosted the flagging campaign of Mike Huckabee, who won the state with some 60 percent of the vote to 24 percent for John McCain, with 88 percent of precincts reporting.

The Vietnam war hero, McCain, is virtually assured of the party's nomination for the November elections, but Huckabee, an ordained Baptist preacher, has been doing well in conservative, rural states.

In a sign that McCain is still viewed with suspicion by many Republicans, a straw poll taken at a conference of conservative activists handed victory to former rival Mitt Romney who dropped out of the race on Thursday.

Some 35 percent of the 1,558 people polled at the conference said they would vote for Romney over 34 percent for McCain, according to Saturday's results.

On the Democratic side with every state race crucial, Clinton and Obama spent early Saturday pitching for votes in Maine, the country's northeastern-most state, which votes on Sunday to decide 34 delegates.

Later Saturday, both were then headed to Virginia, which with neighboring Maryland and Washington, DC, hold primaries on Tuesday where another 200 delegates would be at stake.

Clinton and Obama were also both due to address a key Democratic dinner in Richmond, Virginia late Saturday, the first time they will share a platform since Super Tuesday.

A tally by independent pollsters RealClearPolitics on Saturday put Clinton marginally ahead in the delegate count, with 1,076 to Obama's 1,015 -- with a candidate needing to get 2,025 to clinch the party's nod.

Polls for Saturday's first contests, the Republican and Democratic primaries in Louisiana, opened at 6:00am (1100 GMT).

Democratic caucuses in the midwestern state of Nebraska opened at 9:00am (1500 GMT), while Washington's caucuses opened at 1:00pm (2100 GMT).

A national Newsweek poll out Friday had Obama surpassing Clinton's once-overwhelming lead for the first time.

It gave Obama 42 percent support compared to 41 percent for Clinton.

Nevertheless, in the survey of 1,394 registered voters, a large 17 percent remained undecided, underscoring the need for both candidates to continue fighting for support, voter by voter.

In Washington state, Obama's soaring message of change had registered with voters at a caucus at Mercer Island west of Seattle.

"I'm a big fan of Senator Clinton and I thought long and hard about my decision, but ultimately I think Senator Obama is going to unify and govern in a way that will be very positive for the nation," said caucus-goer Paul Steven-Miller, a former White House policy adviser to President Bill Clinton.

Obama also stood favored to outperform Clinton in Virginia and Maryland, in part due to the high number of African-American voters.

Virginia Governor Tim Kaine said he endorsed Obama because "he is a unifier in times of bitter division. He is an agent of change at a time when our nation needs change." - AFP/ls/ir