He said it counted nine hostile offensive actions out of a total of 41, with the rest being defensive or resulting from unintentional contact with security forces.
Military officials said they were prohibited from providing numbers on combat or casualties during the two months.
The national ombudsman, Jorge Armando Otalora, said in a report Friday that there had been 57 attacks by rebels against civilians or security forces, an average of one per day.
One of them was an attack on a police post in the municipality of Guapi on Dec. 31 in which two police and four civilians were wounded.
The FARC is believed to number about 8,000 fighters, down from about twice that amount a decade ago. Colombia's U.S.-backed military dealt it a series of withering blows during that time, including killing three members of its ruling Secretariat.
Colombia's nearly half-century-old conflict has claimed tens of thousands of lives, most of them civilians.
Associated Press Writer Anne-Marie Garcia contributed to this report from Havana.