5 February 2013 Last updated at 13:32 ET

Colombia ELN kidnap victims are German pensioners

German officials say the two men kidnapped by rebels in Colombia are German pensioners who entered the country on a tourist visa.

Colombia's second largest rebel group, the ELN, said on Monday it had seized brothers Gunther and Uwe Breuer "weeks ago" in northern Catatumbo region.

The rebels said they suspected the two, who are 69 and 72 years old, of being intelligence agents.

The ELN is also holding two Peruvian and a Canadian contractor.

The German Foreign Ministry has set up a crisis group to deal with the abduction.

Ministry officials said Gunther and Uwe Breuer were on a tour of South America when they were taken in Norte de Santander province, near the border with Venezuela.

It is not clear when exactly they were kidnapped.

'Unlikely spies'

In a statement published on their website on Monday, the ELN (National Liberation Army) said that "in the weeks they [Gunther and Uwe Breuer] have been held, they have not been able to justify their presence in the area, and we therefore consider them intelligence agents and will investigate them further".

The statement came three weeks after the ELN kidnapped a group of employees of an international mining firm, also in Norte de Santander province.

At the time, officials said two Colombians, two Peruvians and a Canadian had been taken.

Since then, the number of those seized on that occasion has been upped to six, but the sixth victim has not been identified.

Colombian President Juan Manuel Santos demanded the ELN free all of those it held immediately.

He also questioned the ELN's motives behind their latest kidnapping.

"Who on earth could think that these German citizens were spying, spying on what here in Colombia?", he asked.

"This is an excuse that nobody in their right mind would accept or understand," Mr Santos said.

The ELN was formed in 1965, inspired by the Cuban revolution and Marxist ideology.

It has been seen as the more politically motivated of the two rebel groups in Colombia, but has over the past years increasingly resorted to drug trafficking, extortion and kidnapping for ransom to finance its insurgency.

The group says it is interested in engaging in peace talks with the government, but has refused to stop its attacks on civilian and military targets before any negotiations would start.

The government said it would not enter negotiations unless the ELN was willing to show "acts of peace" rather than just words.