Venezuelan ombudsman German Mundarain has said security forces tortured some protesters who were detained during recent anti-government demonstrations.
Troops are accused of beating and kicking detainees
Mr Mundarain, known as the Human Rights Defender, accused troops of a "disproportionate use of force" and the "cruel treatment" of detainees.
He said some of those arrested had been repeatedly kicked and hit with helmets.
But he said none of the deaths which occurred during the protests were caused by the troops.
At least nine people are known to have died in the unrest, triggered by an opposition referendum aimed at ousting President Hugo Chavez.
Mr Mundarain said nearly 200 people were also injured and more than 500 arrested in the demonstrations.
The government has denied the security forces committed any abuses.
Chavez denies any wrongdoing
Mr Mundarain said National Guardsmen employed a "disproportionate use of rubber bullets" when they were deployed to quell rioting and protests which took place between 27 February and 3 March.
Opposition leaders said many of those killed were shot by the troops, but Mr Mundarain dismissed these claims saying no deaths could be attributed so far to security forces because none of the deadly shooting injuries were caused by the regulation automatic rifles they carried.
The ombudsman did say the forces had used excessive force, notably when holding protesters in custody.
"These detentions gave rise to cases in which some officers went beyond the legitimate use of force," he said in the report, citing seven cases of torture and 17 of "cruel, inhumane or degrading treatment".
Human rights groups said detainees were subjected to severe
beatings, burnings, electric shocks and mock executions.
Mr Mundarain called on the government to investigate these cases and prosecute the guilty parties if necessary.
The opposition have been calling for the release of those arrested during the protests
But he also criticised the opposition leaders, accusing them of "instigating violence" and saying that the troops had been fired on by protesters.
This, along with his claim that none of the detainees could be considered political prisoners because they had been disrupting public order, has angered the opposition.
Delsa Solorzano, the legal advisor to the Democratic Co-ordinating Board, described Mr Mundarain's declaration that none of those being held were political prisoners as "unbelievable".
"The Chavez government wants to deny that there are political prisoners and that people died on our demonstrations, how sad. A political prisoner exists because
somebody is defending their political and constitutional rights," he said.