Colombian president Juan Manuel Santos welcomed former FARC rebels at the opening session of parliament as part of the peace deal reached in 2016.
The Farc is now a political party known as the Revolutionary Alternative Common Force with five seats in the Senate and five in the House of Representatives but the former rebels were not welcomed by many in Congress.
President-elect Ivan Duque said former rebels should be prevented from sitting in Congress until they are investigated and pay for crimes they may have committed during the civil war.