Ukrainian MPs have spoken about the tactic used by Russian troops as the country continues its invasion of Ukraine.
MPs have accused Russian President Vladimir Putin's forces of "crimes against humanity", including sexual violence and outlined reports of elderly women being raped and executed.
The reports also detailed children having post-traumatic stress and cities cut off from basic necessities as a result of the conflict.
Read more: Russia bombs theatre where over 1,000 were sheltering in Mariupol, official claims
The MPs said Putin's disappointment with the lack of progress in his invasion had forced him to change tactics and target women and children.
The horrifying reports came as MPs briefed journalists ahead of a meeting with Boris Johnson.
Lesia Vasylenko, Alona Shkrum, Maria Mezentseva and Olena Khomenko were given permission to leave Ukraine by President Volodymyr Zelensky, despite men under 60 currently being forbidden to do so.
Speaking at the briefing, Ms Vasylenko said: "The tactics Russia uses on Mariupol is medieval, siege tactics.
"The city is besieged in the worst tradition of medieval times. People are deprived of food, people are deprived of water. For 14 days it was impossible to get into that city."
She also said humanitarian corridors that were agreed to be opened were a "no-go zone" and had "turned red with the blood of the people" as Russian forces opened fire on civilians.
Ms Vasylenko said crimes were being committed against the "most vulnerable of the vulnerable" and said there had been reports of women being raped in cities near Kyiv.
She said: "These women are usually the ones who were unable to get out.
"We're talking about senior citizens of Ukraine. Most of these women have either been executed after the crime of rape, or they have taken their own lives."
Ms Vasylenko appealed to the British government to assist the victims' families and ensure the crimes were "properly documented" for the International Court of Justice (ICJ).
She said: "It's an extremely painful topic for us to take up.
"Unfortunately, it's still the very beginning of the atrocities that will go on. Putin's army is committing war crimes and crimes against humanity."
She added: "Putin has stolen the childhoods from millions of children across Ukraine.
"We will see a generation of Ukrainians grow up with the burden of war already on their shoulder. Thousands of babies are being born every day, and the first thing they see, and they hear is the missiles and sirens, and they have to spend the first hours of their life in basements."
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