Ukrainian President Volodymyr Zelenskyy will address the U.N. Security Council for the first time Tuesday at a meeting that is certain to focus on what appear to be widespread deliberate killings of civilians by Russian troops. The dead were discovered after the withdrawal of Russian forces from a town on the outskirts of the capital, Kyiv, and have sparked global outrage and vehement denials from the Russian government that it was responsible.

The United Kingdom, which holds the council presidency this month, announced late Monday that Zelenskyy would speak at the open meeting called for Tuesday to discuss the situation in Ukraine. Zelenskyy is to address the U.N.`s most powerful body virtually after it receives briefings from U.N. Secretary-General Antonio Guterres, his political chief Rosemary DiCarlo, and U.N. humanitarian chief Martin Griffiths, who is trying to arrange an immediate humanitarian cease-fire and met with senior Russian officials in Moscow on Monday and will shortly be heading to Ukraine.