The Colombian attorney general on Monday announced authorities had uncovered a suspected terrorist plot to target a meeting between President Ivan Duque and indigenous leaders over ongoing protests.

"We have reliable information that... some armed organized groups, which have infiltrated this social and indigenous movement, would like to carry out a terrorist act that could affect the safety of the president himself," said Nestor Martinez.

Without offering details, the attorney general said his office had "electronic evidence" and "testimony from reliable sources" on the suspected plot.

The meeting had been agreed between the government and members of the indigenous minga movement to end a protest that has for three weeks blocked a key route in the southwest of the country.

The prosecutor said intelligence about the alleged plot had been gathered since Friday, after clues "several weeks ago" of infiltration by armed groups in the minga.