A top Culture Ministry official said on Monday that his office will seek the "most severe penalty" possible against the 37-year-old man from Voronezh who used a metal barrier post to smash the painting's glass frame and strike it several times.
"The mixing of the two can mean that any art work can be a victim (of an attack)", she warned.
Russian media said the man, a builder named Igor Podporin, vandalised the painting for "historical reasons" and later told police he acted under the influence of alcohol after drinking a shot of vodka.
"The painting is a lie", Podporin told the court, Russian news agencies reported.
"Three years is nothing compared to the value of this painting", Aristarkhov said.
The painting depicts Ivan the bad mortally wounding his son in Ivan in a fit of rage, and it is considered the most psychologically intense of Repin's paintings - an expression of the artist's revolt against violence and bloodshed.
The 1885 canvas, "Ivan the awful and His Son Ivan on November 16, 1581", by the Russian realist Ilya Repin, portrays a grief-stricken Ivan holding his son after dealing him a mortal blow, an event whose veracity some Russian nationalists dispute. His image of the tsar is widely accepted as one of his masterpieces. Whether he or perhaps even Tretyakov staff members will be found guilty - some sources say the glass over the painting was not protected with special anti-vandal film - has yet to be determined.
According to Culture Minister Vladimir Medinsky, authors in the West have exaggerated the cruelty of Ivan IV in the course of a "hybrid war". In an interview with the newspaper Komsomolskaya Pravda he denounced Repin as "a Bolshevik" who wanted to sully the tsar and said he would pay for a lawyer for Podporin.
"I'd heard about this painting a long time ago", Podporin was quoted as telling him. When I got to the Tretyakov I couldn't stop myself.
"People think their point of view is the only one that is correct".
Last year, Christian Orthodox militants attempted to torch a cinema showing the film "Matilda", which depicted sex scenes between the last tsar, Nicholas II, and his lover, a ballerina.
Russian police arrested the man shortly after the Friday attack.
In 2016 an art gallery shut an exhibit of work by US photographer Jack Sturges after a pro-Kremlin senator labeled the images child abuse and a protester threw urine at them.