Left-wing rebels were blamed for the bombings
The first blast - blamed on a left-wing guerrilla group, the National Liberation Army - destroyed a building in the town of Peñol, 350km (220 miles) north-west of the capital Bogota, killing a policeman, his wife and child and two other civilians.
The second attack - blamed on the main rebel group, the Revolutionary Armed Forces of Colombia (FARC) - destroyed an underground gas pipeline in the north-eastern department of Guajira, killing at least four people in a nearby building that was enveloped in flames.
In another attack blamed on the FARC, five women and a man were killed in the village of El Habra in the same province.
In the south-western province of Valle del Cauca, the army said rebels dragged four men and a woman from their car and shot them.
Outlawed right-wing paramilitaries also shot and killed 10 peasants in the town of Alejandria, 190km (115 miles) north west of Bogota.
Stalled talks
Police said the paramilitaries accused the peasants of collaborating with the FARC.
The latest violence comes amid growing tension between government and rebel negotiators seeking to restart the stalled peace process.
The government has rejected demands by the FARC as conditions for reopening talks.
The FARC demanded the government halt military operations on the borders of their safe haven in southern Colombia. They said any discussion of a possible ceasefire was impossible while a wave of massacres by right-wing paramilitaries continued.
The government's peace commissioner, Camilo Gómez, said the demands could not be taken seriously.