The bodies of five men tortured and killed by Russian troops were found in the basement of a children's health facility, the Ukrainian Prosecutor General's office said on Monday.
"In the basement of one of the children's sanatoriums, police found the bodies of five men with their hands tied," a statement on Telegram said.
The "unarmed civilians" were "beaten" before being "killed" by "soldiers of the armed forces of the Russian Federation," it said.
Photos showing the bodies accompanied the statement.
An investigation into the circumstances of their deaths has been opened, prosecutor Iryna Venediktova's office added.
The West on Monday called for an investigation into "war crimes" blamed on Russian troops in the Kyiv region, which Moscow denies, but Ukraine calls "genocide".
Dozens of corpses in civilian clothes were discovered at the weekend in Bucha, on the northwestern gates of the Ukrainian capital, in the streets or in mass graves, following the Russian withdrawal.