Colombia's government will ask congress to approve better human rights training for police and increase oversight of officers, President Ivan Duque said on Sunday, amid accusations of police brutality during recent anti-government protests.

The attorney general's office says 20 deaths are linked directly to more than a month of demonstrations against Duque's social and economic policies, while rights groups report dozens killed by security forces.

Excessive use of force during marches has drawn international condemnation and at least three officers are now facing murder charges.

The government will ask Congress to approve the creation of a police human rights directorate, which will seek international help on policy, and a new education directorate for officer training, Duque announced during a ceremony to celebrate police promotions.