BY LESLEY CLARK

Seeking to dispel any concerns that Cuban-American voters will stray from his side, President Bush pledged to push for democracy in Cuba on Friday before a Miami crowd champing at the bit for a mention of the island.

As Bush listed how his administration was working to create a ''free and peaceful'' Iraq and Afghanistan, a central theme of his reelection campaign, the crowd at Miami Arena grew visibly -- and audibly -- restless.

''Cuba!'' one man shouted from the stands.

''Un momento,'' the president replied, as he turned back to his prepared campaign speech.

But when he did turn to Cuba, Bush earned his biggest applause as he opened a new line of attack on Democratic presidential nominee John Kerry, accusing the Massachusetts senator of being soft on Fidel Castro.

''The people of Cuba should be free from the tyrant. And I believe that enforcing the embargo is a necessary part of that strategy,'' Bush said. ``My opponent has a different approach.''

The visit Friday, part of Bush's pre-convention campaign swing across eight up-for-grabs states, was his first to Miami since he sought to bolster his Cuban-American base by stiffening the U.S. line against Castro with restrictions on travel and cash assistance amid complaints from some exiles that he had failed to live up to his campaign promises.

It was Bush's second visit to Florida in two weeks, indicating how close the race is likely to be in the state.

The president's toughened approach on Cuba has endeared the president to hard-line exiles who had all but threatened to sit out his re-election, but it has triggered a backlash from more moderate Cuban Americans who want to be able to travel and support relatives in Cuba.

Democrats have sought to exploit the emerging division in the reliably Republican voting bloc, but Bush sought to quash those hopes, portraying Kerry as a waffler on Cuba who once derided the trade embargo as a function of the ``politics of Florida.''

He also chided Kerry for criticizing a dissident movement on the island and said the Democrat flipflopped on the Helms-Burton legislation that in 1996 tightened sanctions against Castro.

Mocking Kerry in Spanish, Bush said, ``He voted yes, then he voted no.''

KERRY'S RESPONSE

Kerry's campaign has said he supported Helms-Burton in its early stages, but voted against it because he disagreed with some of the final technical aspects.

And a campaign spokesman suggested Friday that Bush is lashing out because he's nervous about eroding support within a key voting bloc in the state that delivered him the presidency by just 537 votes in 2000.

''For 3 ½ years, he did nothing on Cuba, waiting until an election year to enact a policy that will do nothing to bring down the Castro regime but will hurt the Cuban people,'' said Kerry spokesman Phil Singer. ``His policy has backfired, his support among Cuban Americans has dropped, so now he's launching negative attacks.''

Democrats cite a July poll as proof that Bush's support among Cuban Americans has softened. The poll showed Bush's support dropping to 66 percent, from his generally stratospheric support that hovers in the 80s.

But Republicans note the poll was sponsored by travel operators who have been hit by the restrictions. They countered with a WLTV-Channel 23 poll conducted Aug. 20-22 that shows eight in 10 Cuban American voters in Miami-Dade backing Bush.

The crowd at Friday's rally was adulatory, but nearly half of the arena was empty, even after the Bush campaign went on Spanish radio to push the free tickets.

A spokesman for the campaign pegged attendance at 8,000 and said officials were not expecting a full house, given the Friday night timing of the event and its proximity to the MTV Video Music Awards.

Outside, about 150 protesters, many of them Cuban Americans, rallied against Bush.

One protester said the Bush administration has strained family ties among Cubans in Cuba -- and here in South Florida.

Julio Torres, 26, waved a ''Cubans for Kerry'' sign while his father, Daniel, was inside with the Bush supporters.

''He's like a lot of older Cubans who think the only way to bring Castro down is by force. I'm into newer tactics,'' Torres said.

HURRICANE AID

Bush also sought to court another potentially massive voting bloc: those affected by Hurricane Charley. He made his first Florid stop a visit to a Miami firehouse, where, flanked by his brother, Gov. Jeb Bush, he got a briefing and pledged to seek $2 billion in federal aid for the state.

Gov. Bush didn't accompany his brother to the rally, allowing the president to boast: ``He's working. He's doing what the people of Florida expect him to do, and that is to do his job.''

Herald staff writers Matthew I. Pinzur, Karl Ross and Michael Vasquez contributed to this report.