A motorcycle bomb attack blamed on Colombia's FARC rebels killed one person and wounded at least 25 after a local truce by the guerrillas ended, an official said Thursday.

The attack took place near a local government headquarters in the western municipality of Pradera, Mayor Adolfo Leon told the RCN radio station, noting that "of the 25 wounded, six are critical."

He said the FARC was responsible, while Colombian President Juan Manuel Santos condemned the bombing as a "terrorist act".

The motorcycle had been loaded with explosives and placed in front of the building, according to Leon. The payload was then detonated, causing casualties and leaving several buildings damaged.

Three policemen were said to be among the wounded, according to a regional police official.

On Wednesday, the FARC ended a month-long holiday season truce that had been a gesture of goodwill during the peace talks with the Colombian government that are taking place in Havana.

Santos, whose remarks about Thursday's bomb were aired on Twitter, alluded to the peace talks, noting that such an act amounted to "irrational and contradictory" action by the FARC.