Ukraine's leader said Thursday he was "deeply concerned" by Poland's adoption of a controversial Holocaust bill which was designed to defend the country's history but has instead sparked an uproar.
The Polish legislation stirred outrage in Israel as it sets penalties for anyone who refers to Nazi German death camps as Polish or accuses Poland of complicity in the Third Reich's crimes.
But a different passage of the bill allows for the prosecution of anyone who denies war crimes committed by Ukrainian nationalists in a move which has sparked an outcry in Kiev.
"I am deeply concerned by the decision of the Polish parliament," Ukrainian President Petro Poroshenko wrote on Facebook
"Historical truth calls for a frank conversation and dialogue and not prohibitions. The assessments which this decision contains are totally biased and completely unacceptable."
Poroshenko said the legislation violated principles of "strategic partnership" between the two countries, saying Ukraine remembered "common victories and the fight against totalitarian regimes."
Some historians say Ukraine's UPA nationalists committed atrocities during World War II, notably against Poles in Ukraine.
In Poland, however, UPA fighters were seen as death squads who were responsible for the ethnic cleansing of Poles from what is now western Ukraine.
In 2015, Ukraine's parliament gave unprecedented recognition to those who served in the UPA, recognising them as "Ukrainian independence fighters".
- Ties strained -
Earlier on Thursday Poland's senate approved the bill, after the lower house of parliament passed the measure last week.
The bill, which must still be signed by Polish President Andrzej Duda before it becomes law, allows the prosecution of anyone who denies crimes committed in 1925-1950 by Ukrainian nationalists, including those who collaborated with Nazi Germans.
Volodymyr Vyatrovych, head of the Ukrainian Institute of National Remembrance, denounced the Polish bill as a "political diktat."
"I am convinced that the law will harm Ukrainian-Polish relations," the historian said in televised remarks.
Ukraine and its EU neighbour Poland have close ties.
Warsaw supported Kiev after a 2014 popular uprising in Ukraine ousted a Kremlin-backed president, leading to Moscow's annexation of Crimea and the outbreak of a Russian-backed insurgency in the east of the ex-Soviet country.
But over the past months ties have suffered over a number of hugely sensitive issues.
Poland's rightwing-dominated parliament in 2016 stirred Ukrainian anger by recognising as a "genocide" the massacre of some 100,000 Poles by Ukrainian nationalists during World War II.
Warsaw for its part has denounced Ukraine for banning the exhumation of Polish victims of wartime massacres by Ukrainian nationalists.
Duda has promised to review the legislation.
dg/as/hmw