Poland's prime minister has called for "truth" and "mutual respect" at an event on rebuilding Ukraine that Volodymyr Zelensky skipped amid a diplomatic row between the two neighbours and allies.
Donald Tusk opened the Ukraine Recovery Conference in Gdansk without the Ukrainian president after he was stripped of Poland's highest state honour over the naming of a military unit after controversial World War Two fighters.
Warsaw and Kyiv have fallen out over the allusion to the Ukrainian Insurgent Army (UPA), who many Ukrainians consider freedom fighters but who Poland accuses of genocide.
The row comes as Ukraine seeks further support and investment as it continues to fend off Russia's full-scale invasion.
"We can build the future only on truth, on mutual respect, on an understanding of history," Tusk told the annual event on Thursday.
Zelensky has led Ukraine's delegation to the conference in previous years, but this year it is being headed by Prime Minister Yulia Svyrydenko.
Polish President Karol Nawrocki branded Ukraine's decision late last month to name a unit after the Ukrainian Insurgent Army (UPA) "outrageous", "incomprehensible" and "deeply disappointing".
Many in Ukraine regard the UPA, which existed in the 1940s and 1950s, as heroes who fought for Ukrainian independence against the Soviet Red Army, as well as Nazi Germany and Polish authorities.
Poland, however, accuses the UPA of carrying out a genocide of around 100,000 ethnic Poles in Volhynia (now Volyn in Ukraine) between 1943 and 1945.
"It hurts not only our historical memory. It also undermines the trust built up over the years and in recent months," Nawrocki added.
While Nawrocki has stressed the row would not impact Poland's support for Ukraine in its war with Russia, it comes as Kyiv is seeking billions in aid and investment in post-war reconstruction - and as it hopes to demonstrate it is ready to accede to the EU.
Both issues will be key topics of discussion at the two-day summit.
Zelensky said this week that he had returned the Polish Order of the White Eagle, which had been bestowed on him in 2023.
He wrote that Ukraine would "remain open to all meaningful formats of engagement with Poland in order to try to avoid conflicting interpretations of the difficult and painful chapters of our shared past".
He added Ukraine was "grateful to the Polish people for their support and co-operation".
It came after Tusk attempted to dampen the diplomatic tensions, saying the feud "delights" Russian President Vladimir Putin, and calling on Zelensky and Nawrocki to "calm emotions, not to stoke tensions".
