By JUAN FORERO

BOGOTÁ, Colombia, May 5 — As army troops began a rescue effort this morning, Marxist guerrillas executed a provincial governor, a former minister of
defense and eight others they had been holding hostage in the mountains of northern Colombia, the presidential palace said in a statement released late tonight.

Elite combat troops dropped into the heavily forested area near the town of Murindo found nine bodies, including those of Gov. Guillermo Gaviria of Antioquia
Province and Gilberto Echeverri, a former defense minister. The other seven victims were soldiers, all under the rank of lieutenant. An eighth soldier died later from his
wounds.

The presidency said some victims had been shot in the back of the neck or behind the ear. Three soldiers who had also been held captive survived the ordeal, the
government said.

The statement said the survivors reported that when the guerrillas heard the army helicopters, a rebel who went by the nom de guerre Paisa "gave the order to murder
the hostages." The government of President Álvaro Uribe, who is from Antioquia and has pledged to step up military strikes against the rebels, insisted that
government troops never engaged the rebels in combat.

The killings shook this country of 40 million people, which has been suffering through a conflict that began in the early 1960's.

"I am really shaken up and appalled," said Ernesto Samper, a former president under whom Mr. Echeverri had served. "This is something without precedent in the
history of the country."

The rebels of the Revolutionary Armed Forces of Colombia, or the FARC, blamed the "fascist army" for the deaths, implying that the 75 soldiers dropped into the
region touched off the violence.

Mr. Gaviria and Mr. Echeverri were leaders of a peace march that moved from the capital of Antioquia, Medellín, to the village of Caicedo in April of last year.
Rebels from the FARC intercepted the marchers and took away the two men.

The rebels have held three American defense contractors since their single-engine plane crash-landed in southern Colombia in February. In all, the FARC is holding
dozens of Colombian politicians and soldiers.