Colombia launched a major military and police operation on Thursday to try and rescue four Chinese oil workers abducted by suspected leftist guerrillas in a remote southern jungle region.

A major land and air operation was under way around the town of San Vicente del Caguan, a long-time stronghold of the Revolutionary Armed Forces of Colombia (FARC) guerrillas that government forces retook in 2002.

The abducted men worked for Emerald Energy, a subsidiary of Sinochem, China's fourth-largest oil company.

Members of FARC kidnapped the workers Tuesday as they drove in a pickup truck near San Vicente de Caguan, Caqueta Province, said Edilberto Ramon Endo, a spokesman for the provincial government.

The Colombian driver of the pickup was also seized but later released by the guerrillas, Endo said.

The Chinese embassy in Colombia confirmed the kidnapping.

The translator is apparently a foreigner but authorities did not confirm his nationality.

Leftists guerrillas have been fighting the Colombian state since the 1960s, but the country's security situation has improved.

Kidnappings, however, have been on the rise recently.

In March, the FARC kidnapped 23 contractors who were doing seismic work for Canadian oil company Talisman Energy in a jungle region in eastern Colombia.

Agencies