Poland's departing President Andrzej Duda visited Ukraine on Saturday and urged Kyiv to be patient during the handover to his nationalist successor, Karol Nawrocki.
Polish president-elect Nawrocki has said he is committed to keep helping Ukraine's defences against Russia's invasion, but has signalled a possible shift in Warsaw's position by opposing Kyiv joining Western alliances such as NATO.
"Please be patient," Duda told reporters at a press conference with Ukrainian President Volodymyr Zelenskiy. "The world looks different from behind the presidential desk, slightly different from what it looks like to a candidate in elections."
Zelenskiy said he would "of course" invite Nawrocki to Ukraine after he assumes office.
Duda's visit was a final gesture of solidarity from one of Ukraine's most vocal wartime supporters as he prepares to hand over the presidency in August.
He was welcomed warmly and awarded an Order of Liberty by Zelenskiy, who is trying to rally support among Kyiv's allies at a crucial juncture in the grinding war with Russia.
Ukraine is struggling to fend off Russian advances on the battlefield and intensifying missile and drone attacks on its cities as diplomatic efforts to end the fighting, now in its fourth year, have faltered.
Neighbouring Poland, where more than 1 million Ukrainians have sought refuge since Russia's February 2022 invasion, has provided key humanitarian, political and military support to Kyiv.
Reporting by Andrew Heavens