Four security officials have been killed in fighting with the Colombian rebel group FARC in the country's south, the defence ministry says.

The ministry said that three soldiers and one police officer were killed in the attack in Caqueta province, where it said they had engaged in "heavy combat" with the Revolutionary Armed Forces of Colombia (FARC).

A foreign journalist and four soldiers are missing after the raid on the military and police anti-drug patrol on Saturday, the defence ministry said in its statement.

Colombian authorities have launched a search operation for the missing after the incident, which occurred in the hamlet of Buena Vista, in the municipality of Montanita.

On Friday, FARC fighters killed at least five government troops in a gunbattle, while three civilians died after a separate attack on a police station.

The former fighting took place in the southwest of the country, on the border between Cauca and Valle del Cauca departments.

A sergeant and four soldiers were among the dead, Jorge Humberton Jerez, a local military commander, told the media.

The police station attack occurred in Caqueta, where Saturday's violence also occurred.

'Political prisoners'

FARC's deadliest attack this year occurred last month, when fighters killed 11 soldiers in the town of Arauquita, near the border with Venezuela.

Earlier this month, the FARC released the last 10 police officers and soldiers they were holding hostage.

Timolean Jimenez, a FARC leader, has recently denied that proposed negotiations with the government imply that the group is prepared to surrender.

About 400 civilians are still being held hostage by the group, according to estimates from the Free Country foundation. FARC denies that claim, but has not released figures of its own.

It says that it has released the last of its remaining "political prisoners" and has pledged to stop kidnappings for ransom.

The FARC has been at war with the Colombian government since 1964, and is believed to still have about 9,000 fighters active in the mountainous and jungle areas of the country.

Source: Agencies