Kremlin critics say the three-day poll was geared to hand United Russia victory and was marred by violations.
The European Court of Human Rights (ECHR) has ruled that Russia was responsible for the 2006 killing of ex-KGB officer Alexander Litvinenko in London.
Tuesday’s ruling by the Strasbourg-based court supported the findings of a lengthy British inquiry that concluded Russian President Vladimir Putin probably approved a Russian intelligence operation to murder Litvinenko.
The ECHR’s ruling said his “assassination was imputable to Russia” as it responded to a complaint brought by Litvinenko’s widow.
The Kremlin critic died aged 43, weeks after drinking green tea laced with rare radioactive isotope Polonium 210 at a hotel in the UK capital.
Russia has always denied any involvement in Litvinenko’s death and quickly dismissed the ECHR’s ruling.
“The ECHR hardly has the authority or technological capacity to possess information on the matter,” Kremlin spokesman Dmitry Peskov told reporters.
“There are still no results from this investigation and making such claims is at the very least unsubstantiated.”
‘Beyond reasonable doubt’
The ECHR’s ruling backed the 2016 British inquiry’s conclusion that former KGB bodyguard Andrei Lugovoy and another Russian, Dmitry Kovtun, carried out Litvinenko’s killing.
Both men have repeatedly denied involvement.
“The court found it established, beyond reasonable doubt, that the assassination had been carried out by Mr Lugovoy and Mr Kovtun,” the ECHR’s ruling said.
“The planned and complex operation involving the procurement of a rare deadly poison, the travel arrangements for the pair, and repeated and sustained attempts to administer the poison indicated that Mr Litvinenko had been the target of the operation.”
Had the men been carrying out a “rogue operation”, Moscow would have the information to prove that theory, the ruling said, adding that the Russian government had not provided such details.
Al Jazeera’s Bernard Smith, reporting from Moscow, said the pair were unlikely to face any justice, given the Kremlin’s rejection of the ECHR’s ruling.
Alleged assassination plots
Despite Moscow’s denials, Litvinenko’s killing has weighed heavily on relations between London and Moscow.
Kremlin critics view the incident as one of several assassination plots hatched by Putin’s Russia, including the attempted poisonings of former agent Sergei Skripal in the UK in 2018 and opposition leader Alexey Navalny in Siberia in 2020. Moscow denies those charges.
British police on Tuesday said a third Russian had been charged in absentia with the Novichok murder attempt on Skripal.
London’s Metropolitan Police force said in a statement that all three individuals charged with conspiracy to murder and attempted murder were members of Russian’s military intelligence service GRU.
The trio was identified as Alexander Mishkin, Anatoliy Chepiga, and Denis Sergeev.