Two staff members of the medical aid agency Medecins Sans Frontieres (MSF) detained by gunmen in Colombia have been freed, the organisation says.
The British and Dutch men were held on Saturday while assessing health services in a guerrilla-dominated province in north-east Colombia.
They were released "without conditions" and had been "treated correctly", MSF said in a statement.
Colombia has one of the highest kidnapping rates in the world.
The majority are carried out by Marxist guerrillas who use the ransoms to fund their 42-year war against the government.
"We are glad that this difficult situation has been brought to an end," Geoff Prescott, director-general of MSF-Holland, said.
"Now our teams can resume their daily work; to bring basic medical attention to the poor and displaced people in Colombia."
The two men were not named but an MSF spokeswoman in London told the BBC the British staff member is head of the mission in Colombia, and the Dutch man is a "logistician".
They were exploring ways of expanding the health services in the Norte de Santander province, some 400 km (250 miles) north-east of Bogota, close to the Venezuelan border.
The two men were prevented from returning to their base on Saturday, the spokeswoman said.
The BBC's Jeremy McDermott in Colombia says the area where they were detained has long been a no-man's land fought over by Marxist guerrillas, right-wing paramilitaries and the army.
The area is also home to drug crops, the revenues of which are used by the warring factions to fund their struggle, our correspondent adds.
MSF has not identified the armed group suspected of detaining the two men, but our correspondent says initial reports suggest it was the left-wing National Liberation Army (ELN).