US Secretary of State Condoleezza Rice has arrived in Colombia for talks aimed at securing a free trade agreement.
Mr Uribe has taken a tough stance against left-wing guerrillas
The visit is also seen as a show of support for the US's closest ally in the region, President Alvaro Uribe.
Mr Uribe is currently engaged in a diplomatic struggle with his neighbour, President Hugo Chavez of Venezuela.
Ms Rice, accompanied by 10 Democratic congressmen, will meet Mr Uribe and some demobilised Colombian right-wing guerrillas on Friday in Medellin.
The Democrats in the US Congress have resisted a free trade pact, accusing Mr Uribe's government of tolerating crimes and human rights abuses by rightist guerrilla groups.
The BBC's Jeremy McDermott in Medellin says the treaty will be a tough sell for Ms Rice.
The Democrats control Congress, while America's mind is on the upcoming presidential elections and President George W Bush is seen as a bit of a lame duck, he says.
The Bush administration is trying to promote the free trade agreement, not as an economic measure, but as an opportunity to support a stalwart ally, he adds.
The White House says Colombia has made great gains in the war on drugs and terrorism, and is a counter-balance to the increasingly hostile Venezuelan leader President Chavez.
Mr Chavez has stated his support for Colombia's Marxist rebels and asked that they be removed from international lists of terrorist organisations.
Medellin, Colombia's second largest city behind the capital Bogota, was the base of cocaine baron Pablo Escobar and one of the world's most violent cities in the last decade.
But it has since been transformed into a manufacturing heartland and a model of progress and urban development, according to our correspondent.
He says the White House worry is that without a trade pact, Colombia's economic gains could come undone, opening the door to the drug traffickers, paramilitaries and Marxist guerrillas waiting in the wings.