George W. Bush yesterday became the first United States president since Ronald Reagan to set foot in Bogota as he tries to strengthen his staunchest Latin American ally.

Bush meets conservative President Alvaro Uribe of Colombia, one of the biggest recipients of United States (U.S.) aid, at the midpoint of a weeklong, five-nation tour shadowed by his leftist nemesis, Venezuelan President Hugo Chavez.

Worried about Chavez?s growing anti-US influence, Bush is seeking to shore up relations with leaders of the right and moderate left in Latin America, where the Iraq war and US trade and immigration policy have made him deeply unpopular.

Although Bush has been to Colombia before, he will be the first US chief executive to visit the country?s capital since 1982, a decision meant to highlight security improvements under Uribe, the most US-friendly leader in the region.

But the White House is not so confident that it will let Bush stay there overnight. The national police chief has warned of leftist rebel attacks during his trip, and a massive security effort has been mounted to keep him safe.He will spend most of his stopover cloistered in Bogota?s Narino Palace, one of Colombia?s most heavily guarded sites.

?The president looks forward to meeting President Uribe to demonstrate U.S. support for Colombia,? said Gordon Johndroe, spokesman for the White House National Security Council. But an emerging scandal tying allies of Uribe to right-wing paramilitary gangs has some US Democrats questioning a White House request for $ 3,9 billion in new aid over the next seven years as well as the wisdom of a US trade deal with Colombia.

The Bogota visit puts Bush next door to Venezuela but Chavez will not be at home. Mounting a rival tour of the region, the fiery populist has hurled insults at Bush at every turn, calling him a hypocrite and an imperialist.

Bush steadfastly refused even to mention Chavez by name during stops in Brazil and Uruguay, where he courted free market-oriented leftist leaders he hopes will counterbalance Chavez and his quest for a regionwide socialist revolution.

?I?ve come to South America and Central America to advance a positive, constructive diplomacy ... on behalf of the American people,? Bush said in Uruguay on Saturday. He has been pushing a softer message of alleviating poverty in a region where the advance of democracy has done little to close the gaping divide between rich and poor.

Reflecting Latin American skepticism over Bush?s transformation, his trip has sparked street protests. His motorcade passed demonstrators wielding banners that read ?Bush murderer? and Bush genocide? on Saturday night in Montevideo.

Chavez, spending a second day in Bolivia and heading for Nicaragua on Sunday night when Bush goes to neighboring Guatemala, blames US policies for the deepening poverty.

In Colombia, Bush is expected to focus largely on Uribe?s fight to win Latin America?s oldest guerrilla war and confront the cocaine trade. Bogota has received more than $ 4 billion in mostly military and anti-narcotics aid from the United States since 2000.

Since taking office in 2002, Uribe has sent troops to repel the Revolutionary Armed Forces of Colombia, or FARC, the largest rebel group, and disarm illegal rightist paramilitaries. Violence has dropped sharply, but the rebels are still a potent force, mainly in rural areas. Colombia also remains the world?s largest cocaine producer, with the United States its biggest market for consumption.

Bush is also expected to try to reassure Uribe about a free-trade agreement signed last year. Democrats who now control the U.S. Congress have demanded changes. After Colombia, Bush travels to Guatemala and Mexico. Like Colombia, they are governed by the right, in contrast to a recent leftward trend in Latin America.

Matt SPETALNICK