KYIV (Reuters) -President Volodymyr Zelenskiy urged the Vatican on Tuesday to contribute to the implementation of a Ukrainian peace plan during talks with a Papal envoy about Russia's war on Ukraine.

Italian Cardinal Matteo Zuppi, tasked by Pope Francis to carry out a peace mission to try to help end the war in Ukraine, visited Kyiv to sound out the Ukrainian authorities.

Zelenskiy said they discussed the situation in Ukraine and humanitarian cooperation "in the framework of the Ukrainian Peace Formula."

"Only united efforts, diplomatic isolation and pressure on Russia can influence the aggressor and bring a just peace to the Ukrainian land," Zelenskiy wrote on the Telegram messaging app.

"I call on the Holy See to contribute to the implementation of the Ukrainian peace plan. Ukraine welcomes the readiness of other states and partners to find ways to peace, but since the war is on our territory, the algorithm for achieving peace can be Ukrainian only."

Zelenskiy met the pope at the Vatican in May and later appeared cool to the prospects of any papal initiative that would put Ukraine on an equal footing with Russia, which invaded in February 2022.

Zelenskiy's plan calls for restoring Ukraine's territorial integrity, the withdrawal of Russian troops and cessation of hostilities, and the restoration of Ukraine's state borders.

A Vatican statement said Zuppi would brief the pope on his meetings and that Francis would evaluate the results and decide on the next steps to take.

The Vatican said before Zuppi's trip that the main purpose was to listen to Kyiv's views on ways "to reach a just peace and support humanitarian gestures that may help ease tensions".

The mention of "humanitarian gestures" appeared to be a reference to Kyiv's request for help in the repatriation of Ukrainian children it says have been illegally deported by Russia but Zelenskiy's statement made no reference to the issue.

(Reporting by Olena Harmash and Philip Pullella, Editing by Timothy Heritage, William Maclean)