Moscow claims that Warsaw did not meet its duty to protect the Russian ambassador from pro-Ukraine protesters.
Russia summoned Polish ambassador to Warsaw on Wednesday, and demanded an apology after his ambassador to Warsaw had red syrup thrown in his face during a wreath-laying ceremony.
The Russian Foreign Ministry said that the attack was a flagrant violation of the international convention of 1961, which states that countries must protect foreign missions.
The Russian side expects an official apology from the Polish authorities and demands that the safety of the Russian ambassador and all staffers at Russian missions in Poland is guaranteed, it said.
On Monday, pro-Ukraine protesters threw syrup at Russia s envoy Sergey Andreyev, when he was about to lay flowers in honor of the fallen Red Army soldiers, as Russia celebrated victory over Nazi Germany in World War II.
The diplomat said on Wednesday that he has not received a formal apology from Warsaw. He said it was hard to believe that Polish authorities were unaware of the attack in advance.
Polish Interior Minister Mariusz Kaminski said shortly after the incident that the behavior of the protesters was understandable given Russia's military campaign in Ukraine. Foreign Minister Zbigniew Rau said the attack was regrettable and that diplomats must be protected.