Up to 50 people died in fighting between Colombian forces and left-wing rebels, as US Secretary of State Madeleine Albright rounded off her visit to discuss US military aid for the Bogota government.

Colombian troops said they had killed 44 guerrillas from the Revolutionary Armed Forces of Colombia (FARC) and suffered six casualties after a 100-strong rebel column attacked a police station at Guayabetal, 60km east of the capital Bogota.

The military used its newly-created rapid reaction force equipped with US-supplied Black Hawk helicopters. Government troops imposed a curfew on all roads leading in and out of the area.

The fighting took place while Mrs Albright discussed increasing co-operation between Colombia and the United States in the fight against drugs.

During her visit, she had talks with President Andres Pastrana about a proposed $1.3bn aid package which is planned for the next two years.

The deal includes the creation of two new US trained and equipped anti-narcotics battalions to add to the one already operational in the south of the country, and 63 more helicopters.

The aid is labelled as purely anti-drug, but is being deployed in FARC-controlled territory. Critics say the package, if approved by US Congress, will drag Washington deep into Colombia's civil conflict.

Peace talks

The latest fighting coincided with a second day of peace talks between FARC leaders and government representatives in a southern jungle.

Negotiations received a boost on Friday when the FARC's legendary leader, Manuel "Sure Shot" Marulanda, attended a session personally and expressed optimism for the peace process.

The military has been keen to avenge a FARC raid last December on a marine base near the border with Panama, where 28 marines were killed in a surprise attack.

At the time, the military claimed to have killed 50 guerrillas in the counterattack, but the rapid reaction force took two days to reach the site and only one guerrilla corpse was recovered.

Mrs Albright's visit to Cartagena on Saturday was surrounded by massive security. More than 1,500 troops and police sealed the city to prevent the threat of any car bombs.

During her trip she got a first hand look at Colombian efforts to intercept cocaine shipments.