BOGOTA (Reuters) - Five people were killed and four wounded after Colombian FARC guerrillas ambushed and attempted to kidnap a candidate for a governor’s post in a southern province, authorities said on Sunday.

The attack underscored the vulnerability of politicians in rural Colombia despite the progress made by President Alvaro Uribe’s U.S.-backed security drive to defeat Latin America’s oldest-surviving leftist insurgency.

Police said rebels attacked a convoy transporting Jose Alberto Perez, a Conservative Party candidate for the Guaviare province governorship in a special February 28 election organized after the previous governor was forced to step down.

Perez was wounded when rebels opened fire in a roadside ambush that killed four police bodyguards and another person, police said.

The FARC, or Revolutionary Armed Forces of Colombia, is at its weakest in decades after Uribe’s campaign to force the rebels back into jungles and mountains. But the guerrilla group remains a threat in rural areas, aided by funds from their involvement in cocaine trafficking and extortion.

Sunday’s attack came as Colombia prepares for legislative elections in March and a presidential vote in May with Uribe still uncertain about whether he will run for a consecutive third term in the world’s No. 3 coffee exporting nation.

In December, the FARC kidnapped and killed a governor of Caqueta State in a rare urban assault. Luis Cuellar was dragged from his home, bundled into a waiting jeep and later found with his throat cut.

Once a mighty peasant army that controlled large swaths of Colombia, the FARC has been battered by the loss of several top commanders and a flood of desertions as its fighters come under increasing military pressure.

Colombia’s troops are benefiting from better mobility with helicopters, improved training and intelligence, forcing the FARC to turn to ambushes and improvised landmines to attack troops.