The army was searching Tuesday for 13 doctors who were kidnapped by Colombia's largest rebel group as they carried out a medical mission in the south of the country.

The doctors had been on a 10-day mission to remote communities and Indian tribes amid the jungles and rivers of Putumayo province, near the border with Ecuador, when they were abducted Monday by the Revolutionary Armed Forces of Colombia, or FARC, authorities said.

CountryWatch: Colombia

"This group is breaking the protocol of the Geneva Convention which forbids ... targeting doctors and paramedics," the Ministry of Social Protection announced in a statement.

Before the abduction, the doctors had been scheduled to finish the mission and return to their hospital in Putumayo's capital Tuesday.

Putumayo is one of Colombia's more lawless zones, home to coca-growers, far-right paramilitaries and leftist rebels.

Colombia has one of the world's highest kidnapping rates, as leftist rebels and common criminals abduct people for ransom or to pressure the government.

The army reported over the weekend the kidnapping and release of nine environmental researchers by the FARC in the north of the country.