By Jeremy McDermott BBC correspondent in Bogota

Suspected Colombian rebels of the National Liberation Army, or ELN, stopped a school bus in the province of Norte de Santander, by the Venezuelan border, and kidnapped six children, later releasing five of them.

Uribe is unlikely to give in to ELN blackmail

The Colombian Government has since begun tentative contact with the group to see if common ground for a peace process can be found.

The incident began as two gunmen boarded the school bus in the town of Ocana.

The bus was later found abandoned by Colombian security forces, with the gunmen taking just one boy with them - 14-year-old Kevin Alexander Rojas.

Grisly industry

Kevin is the 228th child to be kidnapped this year in what has become a new twist in this grisly industry, worth more than $100 million per annum.

Uribe may decide to turn his war machine against the ELN

One person is abducted every three hours on average in Colombia, but recently kidnappers have been taking children rather than adults as they have found the ransoms come a lot faster as desperate parents sell everything to get their children home.

The ELN is one of the main kidnappers in Colombia, using ransoms to fund its 38-year war on the state.

But this kidnapping may not be about money, just as a mass kidnapping of 28 tourists by the ELN last month was not for ransom.

'War-footing'

The group is looking to start a peace process with the government of hardline President Alvaro Uribe.

The Uribe administration has admitted there are contacts going on with the group to see if common ground can be found to start a dialogue.

Last month's mass kidnapping, and perhaps this latest one, may be to pressure the government into starting a peace process on the ELN's terms.

But the guerrillas have probably under-estimated this government.

President Uribe is moving Colombia onto a war footing, having introduced an unprecedented set of security measures and pledging to re-conquer half of the country currently under the domination of the warring factions.

He is unlikely to give in to blackmail from the ELN, and may just decide to turn his growing war machine against them.