Russian prosecutors on Friday warned an independent election monitoring group that it was illegal to hold a planned online parallel vote count during this weekend's presidential ballot.

"The publication of survey results associated with ongoing elections is forbidden on polling day," the prosecutor said in a statement, citing Russian electoral law.

Monitoring group Golos (Voice or Vote) had intended to put text-message reports of results from individual polling stations online in real time during Sunday's election as a safeguard against the potential falsification of vote-count protocols.

Western-funded Golos, which reported mass fraud in December parliamentary elections won by Prime Minister Vladimir Putin's governing party, has repeatedly complained of pressure from the authorities.

The monitoring group has also been criticised by Putin, who has accused it of being part of Western attempts to influence Russian politics.

Founded in 2000, Golos says it does accept Western grants but only because Russian businesses are scared of supporting it.

Golos said Friday that it had not received information so far about alleged fraud during early voting.

"Indications of violations during early voting have not reached us," Golos director Grigory Melkonyants told Russian news agency Interfax, although he expressed concern about voting in polling stations set up for Russian citizens outside the country, which independent monitors are unable to observe.