Colombia’s FARC rebels came under heavy pressure Monday to free a general whose kidnapping prompted the government to suspend peace talks, throwing the two-year-old negotiations into crisis. The talks, the most promising effort yet to end Colombia’s 50-year-old conflict, were derailed Sunday when General Ruben Alzate disappeared in a remote region on the Pacific coast in what the government denounced as a kidnapping by the Revolutionary Armed Forces of Colombia. After an emergency meeting with top army brass, President Juan Manuel Santos called off the talks — which had been due to resume Monday in Cuba — and sent his defense minister to the isolated department of Choco to lead the investigation into the disappearance. The general was abducted along with Corporal Jorge Rodriguez and adviser Gloria Urrego, the captain told commanding officers back in Choco’s capital Quibdo.