Marcin Przydacz, head of the presidential International Policy Bureau, told reporters on Monday that invitations to foreign partners were issued jointly by Prime Minister Donald Tusk and Ukrainian President Volodymyr Zelensky.
Since Nawrocki was not invited, he said, "he will not be attending an event he was not invited to by the prime minister" – and nor will any officials from his office.
Government spokesman Adam Szłapka said the lack of an invitation simply reflects "the format of the event", adding that the presidential office had shown no interest in taking part anyway.
A Ukrainian presidential adviser, Dmytro Lytvyn, said it would not be appropriate for Kyiv to invite Poland's head of state to an event held in his own country, calling it "an internal Polish matter".
The conference, taking place on 25–26 June in Gdańsk and co-hosted by Warsaw and Kyiv, aims to boost international support and investment for Ukraine's reconstruction.
It comes against a tense diplomatic backdrop.
In late May, Kyiv named a military unit in honour of the UPA, the Ukrainian Insurgent Army, a nationalist force that is held responsible for massacres of tens of thousands of Polish civilians in Volhynia and Eastern Galicia between 1943 and 1945.
Poland officially regards the killings as genocide, while Ukraine generally rejects that label, viewing the events as part of a wider wartime conflict in which both sides committed atrocities.
Nawrocki responded by stripping Zelensky of Poland's Order of the White Eagle, the country's highest honour.
Zelensky has since returned the medal, while several former Ukrainian leaders and officials have renounced Polish state awards in solidarity.
Przydacz also accused Ukrainian officials of "ingratitude" toward Poland and rejected suggestions from Kyiv that Warsaw's stance was pro-Russian, calling such claims "insolent".
He said Ukraine had also pulled out of a planned meeting between the two presidents in Warsaw, proposing a later date instead.
(ał)
Source: PAP