Attorney general Luisa Ortega said in a public speech that 55 people have been killed so far in the unrest: 52 civilians and three police.
She added that 771 civilians and 229 security officers have been injured.
"More than half of the cases of people being injured have been due to the action of the security forces. It is worrying how the violence has worsened," she said.
Ortega said a National Guard military police officer was to blame for the death of Juan Pernalete, a 20-year-old student struck by a tear gas canister in a protest in Caracas on April 26.
The wave of unrest since April 1 has seen riot police fire tear gas at masked protesters hurling Molotov cocktails.
"We condemn violence wherever it comes from," Ortega said. "Demonstrations must be peaceful."
Protesters are demanding early elections to remove Maduro. They brand him a dictator and blame him for an economic crisis that has caused food shortages.
The socialist president is resisting that call, accusing the opposition and the United States of attempting a coup against him.
Ortega is the most high-profile public official to criticize the authorities during the protests.
She is a traditional ally of Maduro, but had broken ranks with him over efforts by the courts to strengthen the president's hold on power.
She said the public prosecution service was investigating seven cases in which suspects were allegedly tried by military courts when they should have gone before civilian ones.
Legal rights group Foro Penal said 161 people have been jailed by military courts in recent weeks over the unrest.
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