The head of South Ossetia's state security service, the KGB, has warned that the situation in South Ossetia could get out of control.
Boris Attoyev said there was evidence that some protesters were being "provoked to illegal actions," but he did not say by whom.
Supporters of disqualified presidential candidate Alla Dzhioyeva marched on the government building earlier on December 1.
Attoyev said some of the protesters were being encouraged to storm the building.
The situation in South Ossetia remains tense after Dzhioyeva appeared to be winning the November 27 presidential runoff
in South Ossetia.
Preliminary results announced by the Central Election Commission showed her well ahead of her opponent, Emergency Situations Minister Anatoly Bibilov, who was supported by Moscow.
Bibilov's Unity party complained about violations during the November 27 poll and South Ossetia's Supreme Court agreed and declared the election invalid
The parliament later disqualified Dzhioyeva as a candidate for the repeat presidential election rescheduled for March.
Dzhioyeva has declared that she won the election and has filed a complaint for the Supreme Court to overturn its decision.
Meanwhile, Georgian Interior Ministry official Shota Utiashvili has called South Ossetian accusations of Georgian interference in these events "absolute rubbish."
South Ossetia broke away from Georgia in a war in the 1990s.
Russia recognized South Ossetia's independence after a brief war with Georgia in 2008 but since then only a few other countries have followed the Kremlin's lead.
compiled from agency reports