Marina Ovsyannikova flashing the anti-war poster during live news on Sunday evening.

A dissenting employee of Russia’s state-controlled broadcaster Channel One, who disrupted an evening news show on Monday with anti-war poster, is missing, human rights group OVD-Info has claimed. The employee, identified as Marina Ovsyannikova, was taken to a police station after the breach.

A tweet translated from OVD-Info’s official handle said: “A pre-investigation check was initiated against Channel One employee Maria Ovsyannikova, who came out with an anti-war poster during the live broadcast of the Vremya program, TASS reports citing its source. Where she is is still unknown.”

The organisation monitors detentions at opposition protests.

The incident, a highly unusual breach of security at the channel, took place during its flagship 9:00pm news show called Time. The show is watched by millions around the country, particularly by older Russians.

As the news anchor Yekaterina Andreyeva launched into an item about relations with Belarus, Ovsyannikova, who wore a dark formal suit, burst into view, holding up a hand-written poster saying “No War” in English.

Below, the poster said in Russian: “Stop the war. Don’t believe the propaganda. Here they are lying to you.” It is signed in English: “Russians against the war”.

The protester managed to say a few phrases in Russian, including “Stop the war!”, while Andreyeva, who has presented the news since 1998, tried to drown her out by speaking louder.

The channel then switched hastily to footage of a hospital and Ovsyannikova taken to police station.

Pavel Chikov, a human rights lawyer supporting her, said in a tweet that she has been in custody for more than 12 hours.

Quoting Ovsyannikova’s lawyers, Ukrainian diplomat Olexander Scherba said she can’t be found in any police station.

Her lawyers said she was initially held in the duty room of the television channel’s headquarters in Moscow. They now believe she is being held in a secret location.

Ovsyannikova works at Channel One as an editor.