Ukraine's representatives have handed over to UN Secretary-General Antonio Guterres a list of Ukrainians illegally held in Russia, Ukraine's Permanent Representative to the United Nations, former Ukrainian Ambassador to Russia Volodymyr Yelchenko has said.

"There was a touching telephone conversation with Valentyn Karpiuk Jr., the brother of Mykola Karpiuk, a political prisoner who is serving an illegal prison term in Russia. He is one of those on the list of the Kremlin's prisoners, which has just been handed over to the UN Secretary-General," Yelchenko wrote on Twitter on Monday.