GWEN IFILL: Next tonight: a second day of political protests in Russia.
Jonathan Rugman of Independent Television News narrates this report.
JONATHAN RUGMAN: Tonight's crowds were not huge -- on one side, a few hundred opponents of Vladimir Putin, who accuse him of trying to steal Sunday's parliamentary election, and, on the other, a few hundred Putin supporters, just as adamant that Russia is nowhere near an anti-Putin revolution.
Then riot police moved in, the Kremlin apparently determined to snuff out the merest whiff of dissent. An opposition leader, Boris Nemtsov, was amongst those detained, in what is not a crisis for Putin's Russia, but a new kind of challenge nonetheless.
This was Mr. Nemtsov last night, chanting, "Russia without Putin," leading a crowd of several thousands in Moscow's biggest anti-Putin protest in years -- 300 were arrested yesterday. And while they claimed Mr. Putin's United Russia party had stolen the vote, European election observers agreed it wasn't fair.
SECRETARY OF STATE HILLARY CLINTON: The preliminary report by the OSCE cites election day attempts to stuff ballot boxes, manipulate voter lists, and other troubling practices. Russian voters deserve a full investigation of electoral fraud and manipulation.
JONATHAN RUGMAN: And the scandal is growing. The TV reporter dressed in red has barged into a polling station where it's alleged that someone has been buying votes.
In the toilet, he finds voting papers marked in favor of Mr. Putin's party, which it is claimed will be added to the total. In this Internet video, an investigator says he's found pens in a couple of polling booths with reversible ink, so the vote can be changed if the cross hasn't appeared in the right place.
Today saw a remarkable show of force, with soldiers and police flooding the streets of the capital. Anywhere else, this might be judged an overreaction. In Moscow, it's a mark of just how unused to criticism Mr. Putin is.
Still, this pro-Putin youth demonstration near the Kremlin came as a reminder that the prime minister is still very much in charge. He's on course to win a third term as president next March. And in a show of strength, he said a government reshuffle wouldn't happen until then.
VLADIMIR PUTIN, Russian Prime Minister (voice-over): There are those who say the ruling party is the party linked to robbery and corruption. If we remember the Soviet era, who was in power then? Everyone called them thieves and corrupt people. In the 1990s, it was the same. But it is important how effectively the current government is able to fight such negative statements.
JONATHAN RUGMAN: Mr. Putin's critics say part of that fight is intimidating his opponents. Two men, one a well-known blogger, were today given 15-day prison terms for organizing yesterday's demonstration and disobeying police.