YEREVAN -- 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.
The Armenian Health Ministry said that Seryozha Avetisian, 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.
RFE/RL's correspondents in Gyumri report that additional Interior Ministry troops were entering Gyumri on January 19 after news of the boy's death was reported.
WATCH: Busloads of extra police arrive in Gyumri.
Russian President Vladimir Putin spoke to Armenian President Serzh Sarkisian by phone on January 18 and expressed his condolences to Avetisian’s relatives and "the Armenian nation as a whole," offering to send a plane to take the wounded boy to Moscow for medical care.
Armenia's parliament announced earlier on January 19 that the Gyumri tragedy and legal issues related to it will be discussed by lawmakers on January 20.
Russia's Investigative Committee says that its chief, Aleksandr Bastrykin, will arrive in Yerevan on January 19 at the invitation of his Armenian counterpart, Agvan Ovsepian, to discuss the Gyumri tragedy.
Armenia's Investigative Committee said on January 19 that dozens of people, including Avetisian's relatives and neighbors, as well as Permyakov's fellow-soldiers, had been interrogated regarding the massacre and samples of their hair, blood, and urine had been taken for DNA tests.
Gyumri Mayor Samvel Balasanian held talks with the acting commander of Russia's border guards in Armenia, Sergei Merzlikin; the commander of the Russian 102nd military base in Gyumri, Andrei Ruzinsky; and the deputy police chief of Armenia's Shirak Province, Ashot Grigorian.
They agreed that Russian commanders must increase discipline at the base.
The killings are testing ties between Russia and Armenia, which has just joined the Moscow-led Eurasian Economic Union and hosts the base that is Moscow's biggest foothold in the strategic South Caucasus.