With temperatures forecast to drop as low as minus 17 degrees Celsius during Saturday's march and protest rally, organizers on Monday urged those planning to attend to take extra precautions in order not to suffer.

"We urge anyone who is going to come to dress warmly — do not be shy — hats, mittens, warm sweaters and boots are a must," opposition leader Vladimir Ryzhkov told Interfax. "Come with a thermos of tea, and along the route we will also try to organize some tea."

He said organizers were hoping to keep the rally at Bolotnaya Ploshchad at the end of the 1.5-kilometer march as short as possible — perhaps just 30 to 40 minutes. The federal weather service predicts temperatures at minus 12 C to minus 17 C during the day Saturday.

"We will discuss in detail every aspect related to weather conditions when the organizing committee meets" on Tuesday, said Left Front leader Sergei Udaltsov, according to Interfax.

A brutal cold snap has swept through Eastern Europe in recent days, killing 36 people across six countries — 18 of them in Ukraine — and forcing officials to shut schools and dig out towns buried under abnormal drifts of snow, The Associated Press reported.