BOGOTA, Jan 28 (Reuters) - Colombia stepped up search-and-rescue operations on Monday for two police patrolmen seized by FARC guerrillas in the first kidnapping of security forces in more than a year, which may muddy peace negotiations between the government and rebels.
The Revolutionary Armed Forces of Colombia, the biggest armed group in Latin America, vowed last year to abandon kidnapping for ransom but never said it would stop taking members of the armed forces as "prisoners of war."
"There are operations in the area by the army which are trying to free our police officers," Colonel Nelson Ramirez, the police commander in Valle de Cauca, told reporters.
The kidnapping threatens to increase tension in Cuba as the government and rebels seek a peace accord to end almost five decades of armed conflict.
President Juan Manuel Santos took the biggest risk of his political career by starting the talks and has faced pressure from opposition leaders who say he has allowed the rebels to get the upper hand during negotiations.
The FARC ended a two-month unilateral ceasefire on Jan. 20.
"The practice of kidnapping cannot continue and less so when FARC representatives are taking part in peace talks," Vice President Angelino Garzon told journalists.
The patrolmen, who were kidnapped in the southwestern province of Valle de Cauca during the weekend, were the first security forces taken hostage since rebels said in February 2012 they would stop kidnapping to finance their activities.
The FARC released all the security forces under its control in April last year.
Over its history, the FARC has held dozens of politicians, police officers and soldiers hostage, including French-Colombian Ingrid Betancourt seized in 2002 and three Americans taken a year later.
Betancourt and the U.S.-defense contractors were rescued by the military in 2008, when Santos was defense minister.
Santos is responsible for some of the harshest blows against the FARC, first as defense minister and then as president, including killing the group's leader Alfonso Cano in 2011.
For more than a decade, U.S.-backed strikes against the FARC have severely weakened the rebels and limited their ability to attack the country's economic infrastructure, helping attract billions of dollars in foreign investment. (Reporting by Luis Jaime Acosta; Writing by Jack Kimball; Editing by Bill Trott)