MONTERREY, Mexico (Reuters) - President Bush told Latin Americans on Monday they had a "God-given right" to freedom in a sharp attack on Cuba's Fidel Castro and other rivals in a region where anti-U.S. sentiment is rising.

Bush patched up his friendship with Mexican President Vicente Fox earlier on Monday after a year of disputes over the Iraq war, but he had only stern words for other Latin American leaders who have fallen foul of Washington.

Speaking at a 34-nation summit of leaders across the Americas, Bush singled out Cuban President Fidel Castro for his toughest condemnation.

"Through our democratic example, we must continue to stand with the brave people of Cuba, who for nearly half a century have endured the tyrannies and repression," Bush said at the summit's inaugural ceremony.

"Dictatorship has no place in the Americas. We must all work for a rapid, peaceful transition to democracy in Cuba," he said.

In recent years, leftist leaders have been elected in Brazil, Argentina and Venezuela. All three countries have established friendly ties with Castro, who has held power for 45 years despite U.S. efforts to oust and isolate him.

Washington's support for sometimes brutal governments in Latin America during the Cold War left many distrustful of U.S. leadership and anti-American sentiment surged last year with the war against Iraq.

LOOKING FOR FRIENDS

Bush hopes to win back some friends and isolate his rivals at this summit in the northern Mexican city of Monterrey.

He said firm support for democracy "gives hope and strength to those struggling to preserve their God-given rights" and referred specifically to Venezuela and Haiti, which have both clashed with the United States.

Venezuelan President Hugo Chavez has resisted opposition demands for a referendum on his rule, and Haiti's President Jean-Bertrand Aristide's government has been rocked by violent protests and allegations of government repression.

Bush largely ignored Latin America over the last two years as he focused on Iraq, Afghanistan and national security.

But he is now seeking support from Hispanic voters for his re-election bid this year, and is trying to win back allies in an increasingly troublesome region. It will be no easy task.

With several Latin American nations opposing Washington on everything from trade to anti-terrorism measures, Bush was anxious to play up his improving relationship with Mexico.

After landing in Monterrey, he went straight into a private meeting with Fox and the two men put aside their disputes over Iraq to praise each other for their work on U.S. immigration reform and the war on terror.

Once close allies, they fell out last year but the up-and-down friendship has been revived by Bush's new plan to overhaul U.S. immigration laws and Mexico's recent tightening of airport security for U.S.-bound flights.

Bush invited the former Coca-Cola executive to visit his Texas ranch in early March, a clear sign that the troubles of last year have eased considerably.

Fox accepted the invitation and applauded the capture of deposed Iraqi President Saddam Hussein as "a very important accomplishment which is for the better of all nations ... all people in the world."

Bush met late on Monday with Brazilian President Luiz Inacio Lula da Silva, a leftist former steelworker who has led opposition to U.S. trade policies.

Lula's government also recently retaliated against new U.S. anti-terrorism measures at airports, requiring that American citizens entering Brazil be fingerprinted and photographed.

Hundreds of people joined a subdued anti-American protest march in Monterrey on Monday. No trouble was reported.

(Additional reporting by Alistair Bell and Steve Holland)