By Nelson Acosta HAVANA (Reuters) – Colombia’s Marxist-led FARC guerrillas on Thursday threatened to end a unilateral truce that has been in place since December unless the government of President Juan Manuel Santos calls off military attacks on rebel positions. The Revolutionary Armed Forces of Colombia (FARC) called a truce at Christmastime and Santos responded on March 10 by announcing Colombia’s armed forces would halt aerial bombing raids for one month, saying the reprieve could be extended if the FARC continued its ceasefire. A day before Santos announced the halt to aerial bombing, the Colombian army said it had killed longtime FARC commander Jose David Suarez, leader of a rebel front near the Panamanian border. “We are asking President Santos to do something to save the unilateral and indefinite called by the FARC.