Faced with social unrest and with only a few weeks left in which to decided whether to run for another term, Colombia's President Juan Manuel Santos has reshuffled his cabinet.

Of 16 cabinet members Santos replaced five -- Interior, Justice, Agriculture, Mines and Energy, and Environment.

He said this new cabinet was determined to achieve peace with leftist FARC rebels, with whom the government is negotiating in Cuba.

Santos is facing unrest from farmers seeking aid to compensate for new cheaper imports from the US under a free trade accord.

Truckers are also disgruntled over fuel prices.

The president's disapproval rating stands at 72 percent, says a Gallup poll.

Santos has to decide by November if he wants to stand for a second term in office.

He runs a broad center right alliance and has ruled since 2010.