UNITED NATIONS - The United Nations is increasingly hearing accounts of rape and sexual violence in Ukraine, a senior UN official told the Security Council on Monday (April 12), as a Ukrainian human rights group accused Russian troops of using rape as a weapon of war.

Kateryna Cherepakha, president of La Strada-Ukraine, said her organization's emergency hotlines had received calls accusing Russian soldiers of nine cases of rape, involving 12 women and girls.

"This is just the tip of the iceberg," she told the council via video. "We know and see - and we want you to hear our voices - that violence and rape is used now as a weapon of war by Russian invaders in Ukraine."

Russia has repeatedly denied attacking civilians since its invasion of Ukraine began on Feb 24.

The United Nations said last week that UN human rights monitors were seeking to verify allegations of sexual violence by Russian forces, including gang rape and rapes in front of children, and claims Ukrainian forces and civil defense militias had also committed sexual violence. 

Ukraine's UN mission did not immediately respond to a request for comment on allegations against Ukraine forces.

"Russia, as we have stated more than once, does not wage war against the civilian population," Russia's deputy UN Ambassador Dmitry Polyanskiy told the Security Council on Monday, accusing Ukraine and allies of "a clear intention to present Russian soldiers as sadists and rapists."

UN Women Executive Director, Sima Bahous, said that all allegations must by independently investigated to ensure justice and accountability.

"We are increasingly hearing of rape and sexual violence," she told the council. "The combination of mass displacement with the large pressure results of conscripts and mercenaries and the brutality displayed against Ukrainian civilians has raised all red flags."

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All sides in the Ukraine war have systems of conscription, where young men are required by law to do military service. Ukraine and Russia have accused each other of using mercenaries.

Russia says it is carrying out a "special military operation" to support independence declarations by separatists in two provinces in eastern Ukraine.

Ukraine's UN Ambassador Sergiy Kyslytsya told the Security Council that the Prosecutor General's Office of Ukraine was "launching a special mechanism of documentation of cases of sexual violence by Russian soldiers against Ukrainian women."