Russian opposition to stage large Saturday protest

BRIAN WILLIAMS, anchor: Overseas tonight, we're just hours away from what could be the start of the largest street protests in Russia in decades and they'll be targeting Vladimir Putin , who a lot of Russians blame for widespread fraud and corruption in national elections this past weekend. Elections in which his own party managed to hold onto power. After protests erupted earlier this week, Putin turned his anger on the US, blaming Hillary Clinton in a cold war of words. NBC 's Stephanie Gosk has more tonight from Moscow .

STEPHANIE GOSK reporting: This week in Moscow , thousands of protesters faced off against police. " Russia without Putin " and " Putin is a thief," they shouted. Rare public defiance following Prime Minister Vladimir Putin 's surprisingly weak showing in Sunday's parliamentary election and allegations of widespread fraud. Even Secretary of State Hillary Clinton was critical, prompting Putin to accuse her of inciting the unrest. But the alleged fraud was all over the Internet , YouTube videos like this one.

GOSK: An election official is confronted after he appears to be filling out multiple ballots. Human rights groups say more than 1,000 people have been arrested since Monday, but the opposition plans another big protest tomorrow. Yevgenia Chirikova was an environmental activist before this week. Now she's a political activist. 'I have small children,' she told me. 'This country has gone downhill and it's Mr. Putin 's fault.' Andrei Griasnov , a computer software developer, says he wants change.

Mr. ANDREI GRIASNOV: All of the government structures are corrupted from the -- from up to the very low down.

GOSK: From the top to the bottom ?

Mr. GRIASNOV: Yeah.

GOSK: By law, Putin had to step down as president in 2008 , but he never really gave up control. Now the former KGB strongman says he will run for the job again in March. Protesters like these hopefully can stop it. The white ribbons are the new symbol of their movement.

Unidentified Man:

GOSK: These guys have already handed out hundreds tonight. The ribbon says "Against the party of crooks and thieves." So far, more than 35,000 people have signed up on Facebook to join tomorrow's protest. The government has approved the demonstration, but not here in Revolution Square where the opposition wants it. Already there are splinter groups that are saying they'll break off and come here anyway, even if it means getting arrested. Security forces are getting ready for what could be Russia 's largest political demonstration since the fall of the Soviet Union , 20 years ago this month. Stephanie Gosk, NBC News, Moscow .