(Adds Clinton campaign response to Trump World War Three statement, paragraph 13)

By Luciana Lopez

COCONUT CREEK, Fla., Oct 25 (Reuters) - Democratic presidential candidate Hillary Clinton warned her supporters on Tuesday against complacency as opinion polls show her holding a clear lead over Republican rival Donald Trump with two weeks left until the Nov. 8 election.

Clinton told voters in Florida, one of the battleground states where the election will likely be decided, that Democrats could not afford to relax.

"I hope you will come out and vote because it's going to be a close election. Pay no attention to the polls. Don't forget, don't get complacent, because we've got to turn people out," she told a rally in Coconut Creek, standing in front of a large sign reading: "Vote Early."

Trump also campaigned in Florida on Tuesday. He blasted recent spikes in premiums for health insurance under President Barack Obama's Affordable Care Act, known as Obamacare. Trump promised to repeal and replace the healthcare law as soon as he takes office.

"This is why we have to drain the swamp and repeal and replace Obamacare immediately, and I'm the only candidate running for president who will do it," Trump said.

On Monday, the U.S. government said the average premium for insurance plans sold on Healthcare.gov for 2017 rose by 25 percent compared with 2016.

But with polls showing Trump trailing Clinton, Trump has asked his campaign to cut back on work identifying candidates for jobs in his future administration and focus instead on bolstering his chances on Nov. 8, according to two people familiar with the campaign's inner workings.



POWELL BACKS CLINTON

An average of national polls on the RealClearPolitics website since mid-October gives Clinton a lead of more than 5 percentage points, as Trump fights off accusations that he groped women and faces heavy criticism for suggesting he might not accept the result of the election if he loses.

Trump denies the accusations of sexual misconduct and says the election is rigged against him, although he has not cited widely accepted evidence to back that up.

On Tuesday, Trump told Reuters that Clinton's plan for fixing the Syrian civil war would "lead to World War Three," because of the potential for conflict with military forces from nuclear-armed Russia.

In an interview focused largely on foreign policy, Trump said defeating Islamic State was a higher priority than persuading Syrian President Bashar al-Assad to step down, playing down a long-held goal of U.S. policy.

Clinton has called for the establishment of a no-fly zone and "safe zones" on the ground in Syria to protect noncombatants.

Her campaign responded in a statement later on Tuesday noting that both Republican and Democratic national security experts had deemed Trump ill-prepared to be commander in chief, and accusing Trump of "parroting" Russian President Vladimir Putin and playing on Americans' fears.

Colin Powell, who served as Republican President George W. Bush's secretary of state and was chairman of the U.S. military's joint chiefs of staff under his father, Republican President George Bush, said on Tuesday he would vote for Clinton.

The two candidates have sparred in recent days over the U.S.-backed Iraqi military push to take the northern Iraqi city of Mosul from Islamic State, which Trump described as a "total disaster."

"He's declaring defeat before the battle has even started," Clinton, who was secretary of state during Obama's first term, said on Tuesday.

She urged supporters to participate in early voting, which began this week in Florida.

"Nobody should want to wake up on Nov. 9 and wonder whether there was more you could have done," Clinton said.

Clinton also appeared on Tuesday at the Univision studio in Doral, Florida, on "El Gordo y La Flaca" ("The Fat Man and the Skinny Woman"), a long-running entertainment show aimed at Latinos. The appearance underscored the importance of Latino voters in the battle for Florida's 29 electoral votes.

Clinton maintained a commanding lead in the race to secure the 270 Electoral College votes needed to win the White House, according to Reuters/Ipsos States of the Nation project results released on Saturday.



(Additional reporting by Steve Holland in Sanford, Fla., and Emily Flitter in New York; Writing by Alistair Bell and Patricia Zengerle; Editing by Leslie Adler and Peter Cooney) ((patricia.zengerle@thomsonreuters.com, www.twitter.com/ReutersZengerle ; 001-202-898-8390; Reuters Messaging: patricia.zengerle.reuters.com@reuters.net))