The US Under Secretary of State for political affairs, Marc Grossman, is expected to discuss Colombia's renewed efforts to tackle left-wing rebels with the backing of millions of dollars from Washington.
The country's newly-elected President, Alvaro Uribe, has declared a state of emergency to fight the guerrillas.
Last month, the US Congress voted to allow Colombia to use more than a billion dollars of US anti-drugs aid to fight the guerrillas and paramilitary groups.
The US has also signalled that a drugs surveillance programme could resume before the end of the year once training for personnel in Peru and Colombia is completed.
The BBC's correspondent in Bogota, Jeremy McDermott says Mr Grossman's visit signals a deepening involvement in the 38-year Colombian civil conflict.
More millions
Washington welcomed Mr Uribe with open arms after he presented himself as the keenest recruit in the war on terrorism, promising to crack down on the three warring factions in Colombia that are on the US terrorism list.
The US responded by lifting restrictions on more than a billion dollars of military aid previously granted by then President Bill Clinton specifically for use in the war on drugs.
This frees up an elite US-trained anti-narcotics brigade and around 70 helicopters to be used against guerrillas such as the Marxist Revolutionary Armed Forces of Colombia (FARC).
FARC greeted Mr Uribe's inauguration with five days of violence that has left more than 100 people dead.
Right-wing paramilitaries have said they would be ready to demobilise their forces immediately if the left-wing rebels showed willingness to start a serious peace process with the new government.
In the meantime, it seems the US handouts will continue - another $140m pledged under a supplementary aid package is expected, with more likely next year.
The United States is also prepared to take on the Colombian guerrillas and drug lords on other fronts.
Drug surveillance
The US ambassador in Bogota, Ann Patterson, has indicated that Washington is preparing to freeze bank accounts linked to Colombian guerrillas that have been traced in the American banking system.
The US drugs tsar, John Walters, has also said drugs surveillance in Latin America could resume by the end of the year.
Peru and Colombia have asked the United States to resume the programme after it was suspended in April 2001, when the Peruvian Air Force accidentally shot down a small civilian plane, killing a US missionary and her child.
Both countries say the flights were a key component of their efforts to fight drug trafficking.
Our correspondent says it seems that the only thing the US Congress will not allow, with the shadow of Vietnam ever present, is the deployment of US troops in combat roles.