Leftist guerrillas are holding an American and a British journalist on assignment for the Los Angeles Times in eastern Colombia, a region the rebels said in a statement today had been "declared a war zone by the North American government and the Colombian state."

The two freelance journalists with years of experience working in Colombia's most violent areas -- Ruth Morris, a British national with U.S. residency status, and Scott Dalton, an American -- were stopped Tuesday in Arauca province by members of the National Liberation Army (ELN). The rebel statement said the two would be released "when merited by political and military conditions."

The detention came a week after U.S. Special Forces troops arrived in Arauca to begin training Colombian forces in their war against the rebels. Morris and Dalton were working on a story about rebel military tactics in Arauca when they came upon a rebel roadblock between the towns of Saravena and Tame. They were led away from their hired car with hoods on their heads, according to the driver, who was released after a night in the rebel camp.

The driver said the rebels told him the journalists had been invited to meet with a higher-ranking ELN commander and were not being held against their will. But the ELN confirmed in a statement broadcast over a clandestine rebel radio station that the two were being held indefinitely in apparent protest over Colombian military operations in the area.

"The situation in Colombia is very fluid and our primary concern is for Ruth and Scott's safety," the Los Angeles Times said in a statement. "We do not feel it would be appropriate to discuss the situation at this time."

The ELN, the smaller of Colombia's two leftist guerrilla groups seeking to topple the government, has staged a number of large-scale kidnappings for political and economic reasons in recent years. Much of the group's income is derived from ransom payments.