(Reuters) - Ukraine on Sunday rebuffed Pope Francis's call to negotiate an end to the war with Russia, with President Volodymyr Zelenskiy saying the pontiff was engaging in "virtual mediation" and his foreign minister saying Kyiv would never capitulate.

Francis said that when things were going badly for a party to a conflict one had to show the ”courage of the white flag” and negotiate. The pope's interview was believed to be the first time Francis has used terms like "white flag" or "defeated" in discussing the Ukraine war, though he has referred in the past to the need for talks.

Zelenskiy made no direct reference to Francis or his comments but mentioned religious figures helping inside Ukraine.

"They support us with prayer, with their discussion and with deeds. This is indeed what a church with the people is," Zelenskiy said in his nightly video address.

"Not 2,500 km away, somewhere, virtual mediation between someone who wants to live and someone who wants to destroy you."

Foreign Minister Dmytro Kuleba, writing on the X messaging platform, said that the strong person in any dispute "stands on the side of good rather than attempting to put them on the same footing and call it 'negotiations'".

"Our flag is a yellow and blue one," Kuleba wrote in English, referring to the Ukrainian national flag. "This is the flag by which we live, die, and prevail. We shall never raise any other flags."

Kuleba also pointed to allegations that Pope Pius XII failed to act against the Nazis in Germany in World War Two.

"I urge (the Vatican) to avoid repeating the mistakes of the past and to support Ukraine and its people in their just struggle for their lives," he wrote.

That was a reference to longstanding arguments that Pius took no action despite evidence that emerged during the war of the extent of the Holocaust. A letter made public last year from the Vatican archives appeared to show that Pius was made aware of details of Nazi actions to exterminate Jews as early as 1942.

Supporters of Pius say he worked behind the scenes to help Jews and did not speak out in order to prevent worsening the situation for Catholics in Nazi-occupied Europe. His detractors say he lacked the courage to speak out on information he had despite pleas from Allied powers fighting Germany.

The head of Ukraine's 5 million-strong Eastern Rite Catholic Church, Archbishop Sviatoslav Shevchuk, also rejected the pope's comments.

"Ukraine is wounded, but not conquered! Ukraine is exhausted, but it stands and will stand!" the church's website quoted Shevchuk as saying in New York.

"Believe me, no one has any idea of ​​surrendering."

Zelenskiy has called for the withdrawal of all Russian troops and the restoration of Ukraine's post-Soviet borders. The Kremlin rules out engaging in talks on terms set by Kyiv.

The pope has upset Ukrainian officials several times in the war, including his call last year to Russian youth to take pride as heirs of tsars like Peter the Great, held up by President Vladimir Putin as an example to justify his actions in Ukraine.

European officials supporting Ukraine in efforts to evict Russian troops denounced the pope's latest comments.

"How about, for balance, encouraging Putin to have the courage to withdraw his army from Ukraine?" Polish Foreign Minister Radoslaw Sikorski wrote on X.

Latvian President Edgars Rinkevics, also writing on X, said:

"One must not capitulate in face of evil, one must fight it and defeat it, so that the evil raises the white flag and capitulates."