KIEV A Ukrainian man smeared Polish President Bronislaw Komorowski with a broken egg when he visited the site of a 1943 massacre of Poles in neighboring Ukraine on Sunday, police said.
The attack followed a move by the Polish parliament last week to recognize the massacre by the Ukrainian Insurgent Army (UPA) during World War Two as "ethnic cleansing bearing the hallmarks of genocide".
The move upset Ukrainian nationalists who view the UPA as heroes and freedom fighters.
On Sunday, Komorowski visited the western Volyn region and attended mass at a Catholic church.
As he emerged from the church "a young man from the crowd tapped his shoulder with his hand in which he was holding a crushed egg", police said in a statement.
The 21-year-old man, a resident of Ukraine's southern Zaporizhia region, has been detained and faces hooliganism charges and up to three years in prison, they said.
It was unclear whether the man belonged to any of Ukraine's nationalist groups, the largest of which, "Svoboda" (Freedom) won dozens of seats in parliament last year, becoming a major political force.
"Svoboda" has criticized the Polish parliament's decision but said it would not seek to disrupt Komorowski's visit.
The territory of Volyn was long disputed by Poland and Ukraine. Historians believe tens of thousands of people died in the massacre during the wartime Nazi occupation.
Seventy years later, public opinion in Ukraine remains split on the insurgent movements which co-operated with the Nazis in hope of driving out the Soviet government and creating an independent Ukrainian state.
In the last days of his presidency in 2010, former Ukrainian president Viktor Yushchenko awarded wartime nationalist leader Stepan Bandera the title "Hero of Ukraine".
The award was annulled by a court under his successor, current President Viktor Yanukovich.
(Reporting by Olzhas Auyezov; editing by Andrew Roche)