The promised release of two hostages held for six months by leftist rebels failed to take place Saturday _ with the government blaming jungle rains and relatives saying the state sabotaged the handover by sending troops to the region.

In a surprise gesture, the Revolutionary Armed Forces of Colombia, or FARC, said March 15 that it would free a police officer and an 18-year old cadet seized last year.

The rebels gave an exact time and place for their handover _ Saturday at noon in the Amazon basin hamlet of Afilador, 340 miles south of the capital.

The handover never occurred.

Colombia's government blamed lashing rains, but relatives of the hostages faulted the government for sending troops to the region.

"It wasn't the weather, it was the government's fault," Alba Patron, mother of captive officer Luis Almanza, told Colombian television, and wept.

The International Red Cross, overseeing the release, said guerrillas and the army had clashed.

"We hope their liberation can take place soon," said Juan Pedro Schaerer, a Red Cross official.

The FARC is holding more than 60 hostages, including three U.S. defense contractors kidnapped in February 2003, when their small plane crashed in the jungles of southern Colombia during an anti-narcotics mission.

The government, backed by European mediators, has proposed freeing 500 jailed FARC insurgents as part of a humanitarian exchange for the hostages.

The FARC said in January it would not negotiate a deal with President Alvaro Uribe, who is expected to win a second term in elections May 28.

The rebels' decision to unilaterally release Almanza and the cadet was seen as an attempt to derail Uribe's election.

To mediate the release, it chose Alvaro Leyva, a presidential aspirant who is running on a platform to jump-start peace talks with the rebels.

The FARC have been trying to overthrow the government for more than four decades.