A 6-month-old boy who was stabbed last week in what authorities say was a brutal attack by a Russian soldier in Armenia has died, RFE/FL reported.

The Armenian Health Ministry said that Seryozha Avetisiyan, who had been the sole survivor of the attack that killed his parents, 2-year-old sister, aunt, and grandparents, died in a Yerevan hospital on January 19.

The ministry said in a statement that the boy had been pronounced dead at 5 p.m. local time in the Holy Mother of God Medical Center in Yerevan.

"Despite lengthy, continuous efforts by local and international experts, the attempts to improve the boy's condition did not bring positive results. The patient's heart, lungs, and kidneys gradually failed, which led to his death," the statement said.

Officials say a conscript at Russia's military base in Armenia, Valery Permyakov, confessed to the attack after Russian authorities apprehended him at the Armenian-Turkish border on January 13.

The attack sparked violent protests last week in Yerevan and Gyumri, the site of the Russian base and the slain family's home, by Armenians demanding the suspect be transferred to Armenian custody.

Meanwhile, Russian authorities say that according to the Russian Constitution, Russian citizens suspected in committing crimes on the territories of other countries cannot be extradited to such countries.