Ukraine's parliament speaker on Thursday offered condolences to the descendants of Poles massacred by Ukrainian nationalists in World War Two, a gesture likely to defuse tensions between the allies ahead of the 80th anniversary of the killings.
Poland has positioned itself as one of Ukraine's staunchest allies since Russia invaded the country in 2022.
However, the Volhynia massacre, in which historians say tens of thousands of Poles perished, has continued to hang over ties between the two nations and become more prominent ahead of the July 11 anniversary of one of the bloodiest days of a series of killings that took place from 1943 to 1945.
"We understand your pain after the loss of your loved ones," Kyiv's parliament speaker Ruslan Stefanchuk said in a speech to Poland's lower house of parliament, the Sejm.
"To all the families and descendants of the victims of the events in Volhynia, I express my sincere sympathy and gratitude for upholding the memory of their ancestors."
Stefanchuk's words came after an unusually public row between the allies concerning the massacre.
In an interview published last Friday, Polish foreign ministry spokesman Lukasz Jasina said that Ukrainian President Volodymyr Zelenskiy should apologise and ask for forgiveness for the events in Volhynia.
This drew an angry response from Ukraine's ambassador in Warsaw, but he subsequently said Kyiv was "open to dialogue".
Other Polish officials have also sought to strike a more diplomatic tone regarding Poland's stance.
"We are on the right track and this speech testifies to the rapprochement of our positions once again," Polish Foreign Minister Zbigniew Rau said after Stefanchuk's appearance in parliament.
In 2013, the Polish parliament recognised the massacre by the Ukrainian Insurgent Army (UPA) during World War Two as "ethnic cleansing bearing the hallmarks of genocide".
Ukraine has not accepted that assertion and often refers to the Volhynia events as part of a conflict between Poland and Ukraine which affected both nations.
Polish historians say that up to 12,000 Ukrainians were also killed in Polish retaliatory operations.
(Reporting by Alan Charlish, additional reporting by Pawel Florkiewicz; editing by Mark Heinrich)