SAN VICENTE DEL CAGUAN, Colombia -- Ingrid Betancourt, a presidential candidate in upcoming elections here, has been reported missing from a former rebel safe haven in southern Colombia, officials said.

Betancourt, 40, insisted on traveling by car to San Vicente, the unofficial capital of the formerly demilitarized zone, despite warnings from Colombian officials that it was highly risky to do so, AFP reported.

"Dr Betancourt, disregarding the advice of officials, decided Saturday to press on to San Vicente Del Caguan," officials in Bogota said in a statement, adding that at present, "her whereabouts are unknown."

The former senator from a distinguished family of politicians was accompanied by two unidentified foreign journalists and a campaign aide -- none of whom has been accounted for.

The group departed Saturday from the town of Florencia -- a trip which should have taken just a few hours -- but has yet to arrive in San Vicente or to be heard from, officials said.

Three years ago, then-newly elected Andres Pastrana handed over San Vicente to leftist rebels from the Revolutionary Armed Forces of Colombia (FARC).

On Saturday, Pastrana visited Colombia's newly liberated war zone, three days after ordering air strikes to retake the territory.

FARC rebels have waged war on Colombia for nearly 40 years in a quest for social justice and aid for the poor. Their struggle and random attacks kill 3,500 people a year here, and has cost more than 35,000 lives since 1990.