A Russian court on Thursday placed former state TV journalist Marina Ovsyannikova, who denounced President Vladimir Putin's attack on Ukraine live on air, under house arrest until October.
On Wednesday, investigators detained Ovsyannikova, 44, and charged her with spreading information about the Russian armed forces deemed false by the government.
The mother of two faces up to 10 years in prison, if convicted.
In March, Ovsyannikova, then an editor at Channel One television, made global headlines when she barged onto the set of its flagship Vremya (Time) evening news, holding a poster reading "No War".
The house arrest is not connected to that particular protest, however.
It is linked to a one-woman protest in mid-July near the Kremlin, when Ovsyannikova held a poster that read "Putin is a murderer, his soldiers are fascists".
Three "blood-soaked" toy dolls were laid on the ground in front of her.
At Moscow's Basmanny district court on Thursday, she was placed in a cage surrounded by several police officers.
She held a sign that read "May the dead children haunt you in your dreams".