Those negotiating with Russia should not eat or drink with them following the reported poisoning of Russian billionaire Roman Abramovich and Ukrainian negotiators, warns Ukrainian Foreign Minister Dmytro Kuleba.
"I advise anyone going through negotiations with the Russian Federation not to eat or drink anything, and preferably avoid touching any surface," Sky News cited Kuleba as saying.
It comes as discussions between Ukrainian and Russian delegations are set to continue in Turkey on Tuesday.
Turkish President Recep Tayyip Erdogan welcomed Russian and Ukrainian negotiators as they arrived at his office in Dolmabahce Palace for talks to end the "tragedy," Erdogan said, adding everyone will benefit from an immediate ceasefire.
Erdogan, who has garnered good relations with both Kiev and Moscow, said he remains optimistic of a ceasefire deal. However, negotiations between the Ukrainian and Russian delegations are proving to be difficult.
Kiev wants a withdrawal of Russian troops from its territories as well as additional security guarantees.
Moscow is demanding that Ukraine renounce its NATO bid, recognize the breakaway eastern Ukrainian separatist areas as separate states and the Black Sea peninsula of Crimea, annexed in 2014, as part of Russia.