An anti-war protester interrupted the main news program on Russian state TV Channel One on Monday, holding up a sign behind the studio presenter with slogans denouncing the war in Ukraine.
The sign, in English and Russian, read: "NO WAR. Stop the war. Don't believe propaganda. They are lying to you here." Another phrase, which looked like "Russians against war," was partly obscured.
The extraordinary protest took place on day 19 of the war that began when Russia invaded Ukraine on February 24 in what it calls a special military operation.
"Stop the war. No to war," the woman protester could be heard shouting, as the news anchor continued to read from her teleprompter.
The protester could be seen and heard for several seconds before the channel switched to a different report to remove her from the screen.
"Wow, that girl is cool," Kira Yarmysh, spokesperson for jailed opposition leader Alexey Navalny, wrote on Twitter.
She posted a video of the incident, which quickly racked up nearly 180,000 views.
State TV is the main source of news for many millions of Russians and closely follows the Kremlin line that Russia was forced to act in Ukraine to demilitarize and "denazify" the country, and to defend Russian speakers there against "genocide." Ukraine and most of the world have condemned that as a false pretext for an invasion of a democratic country.
The woman was named by OVD-Info, an independent protest-monitoring group, and by the head of the Agora human rights group, as Marina Ovsyannikova, an employee of the channel.
Pavel Chikov, head of Agora, said she had been arrested and taken to a Moscow police station.
Tass said she may face charges under a law against discrediting the armed forces, citing a law enforcement source.
On March 4, Russia's parliament passed a law making public actions aimed at "discrediting" Russia's army illegal and banning the spread of fake news, or the "public dissemination of deliberately false information about the use of the Armed Forces of the Russian Federation." The offense carries a jail term of up to 15 years.