Sergiy Andreev was splashed with a red substance as he attempted to lay flowers at the Soviet Military Cemetery in the Polish capital Warsaw, state news agency PAP reported.
May 9 is Victory Day in Russia as the country celebrates overcoming Nazi Germany in the so-called Great Patriotic War.
Russia’s top diplomat to Poland sought to mark the occasion by laying wreaths at the Soviet cemetery in the early afternoon on Monday, but his delegation was met by a crowd of protesters.
Flying Polish and Ukrainian flags, amid chants of “fascists” and “murderers,” demonstrators poured a red substance over Andreev, who returned to the embassy car with his entourage, the PAP news agency reported.
He told reporters he was “proud" of his country and President Vladimir Putin.
Protesters thronged the Russian vehicles, which eventually left the cemetery, news outlets reported.
Andreev was later quoted by Russian media as saying he did not suffer any injuries and did not notify the police, but would “submit a note of protest” to the Polish government over "failure to maintain public order."
Polish foreign ministry 'monitoring developments'
Meanwhile, the Polish foreign ministry said it was "aware of the gravity of the situation and was "monitoring developments.”
It added that "so far there has been no decision" to recall the Polish ambassador from Moscow, the rmf24.pl website reported.
The 19-hectare Soviet Military Cemetery in Warsaw holds the remains of more than 20,000 troops who lost their lives between 1944 and 1945, according to the PAP news agency.
Monday is day 75 of the Russian invasion of Ukraine.
Source: PAP, rmf24.pl, wydarzenia.interia.pl