BOGOTA, Colombia—Colombia's national police director is blaming the FARC for a grenade attack that injured six people on New Year's Eve, and says this breaks a much-publicized truce that the leftist guerrillas unilaterally declared as a goodwill gesture during peace talks.

The government of Juan Manuel Santos rejected the truce proposal, and that same night, New Year's Eve, an Air Force bombing killed at least 13 guerrillas.

Gen. Jose Roberto Leon Riano says the attack on a police station in the remote Pacific village of Guapi injured four civilians and two officers. He held a news conference Wednesday, declaring that the grenade attack proves the FARC is not keeping its promises. The FARC had said in November that its unilateral truce would last through Jan. 20.