WASHINGTON - Secretary of State Hillary Clinton flies to Latin America on Sunday, working to buff a lackluster U.S. image in a region where Brazil is emerging as a regional power with global aspirations.

The trip, featuring Clinton's first stops in South America as secretary of state, includes a visit to Chile on Tuesday, although officials said they were assessing the situation after Saturday's 8.8 magnitude earthquake rocked the country.

Brazil is the centerpiece of Clinton's five-day visit and she will use her March 3 stop there to seek support for the drive on the U.N. Security Council to put new sanctions on Iran over its nuclear program.

Brazil -- a non-permanent member of the council -- has been reluctant to get tough on Iran and analysts say Clinton faces a diplomatic test as she seeks to bring President Inacio Lula da Silva on board in the final weeks before U.N. diplomats unveil the sanctions strategy in New York.

But the trip also marks a fresh U.S. start in Latin America, which saw early hopes for better ties with the Obama administration fade amid disputes over last year's Honduras coup and the continued U.S. embargo on communist-ruled Cuba.

That disappointment was underscored this week when the Rio Group including Mexico and Brazil agreed to form a new regional bloc that explicitly leaves out the United States -- a thumbed nose at a power many feel is still too cavalier in its dealings with its southern neighbors.

Their early expectations were very large, and probably impossible to meet, said Peter DeShazo, director of the Americas program at the Washington-based Center for Strategic and International Studies.

There has been a lot more continuity in policy than people expected.

Latin America-watchers say Clinton's itinerary speaks volumes. The first two stops on the trip, Uruguay and Chile, have both recently held smooth elections and are regarded as models of moderate, market-oriented economies.

She winds up with stops in Costa Rica, another stable longtime U.S. ally, and Guatemala, which has seen its strategic importance skyrocket as a major new front in the battle against international drug traffickers.

She is making the right stops, said Roberto Izurieta, head of the Latin America Department at The George Washington University's Graduate School of Political Management.

She is supporting moderate economic policies and democratic principles. It is the right message.

TOUGH SELL ON IRAN

Despite the Latin America focus, Iran will top the agenda as the United States and other veto-wielding permanent members of the U.N. Security Council, along with Germany, seek to agree on a resolution calling for new sanctions on Tehran.

Russia has sounded more positive about possible sanctions over Iran's nuclear program, which Tehran says is for peaceful purposes but which western powers fear is a cover for building atomic weapons.

But China has called for more talks, and Brazil -- which hosted Iranian President Mahmoud Ahmadinejad in November -- is also reluctant, a position Clinton may not be able to change.

Julia Sweig, director of the Latin American program at the Council on Foreign Relations, said Brazil's own experience with both nuclear energy and democratic transformation made it leery of U.S. saber-rattling over Iran's current crisis.

They see themselves as having had an experience both in shifting toward a peaceful nuclear program and in shifting to democracy that Iran might have the potential to undergo right now, Sweig said.

They are still insisting on not isolating Iran, though I don't know how long they will be able to play that out.

Brazil has also pushed for a change in U.S. isolation of Cuba -- Lula payed an emotional visit to the island last week -- and those calls are likely to be repeated during Clinton's two stops in Central America.

While the Obama administration resumed migration talks with Cuba that had been suspended by former President George W. Bush in 2004, it has been cautious on any broader policy change despite repeated prodding by its Latin American neighbors.

Clinton is also likely to be pressed on Honduras, which is struggling to return to stability and legitimacy after a coup last year toppled President Manuel Zelaya.

The United States helped to broker new democratic elections in November that brought President Porfirio Lobo to power. But Washington was widely accused of failing to take a strong enough line on Zelaya's ouster -- raising bitter memories of U.S. support for past military coups in the region.

She's got to make up for lost time, especially over Honduras, Sweig said. American credibility has really taken a hit.

(Reporting by Andrew Quinn, editing by Anthony Boadle)

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