US President-elect Donald Trump spoke with Russian President Vladimir Putin, the first phone conversation between the two leaders since Trump won the election, The Washington Post reported.

The US daily, on Sunday (local time) citing its sources, said that Trump took the call from his Mar-a-Lago resort in Florida and during the conversation advised the Russian president not to escalate the war in Ukraine.

Neither the White House nor the Kremlin have officially confirmed this information.

During the call, the Preseident-elect reminded Putin of Washington’s sizable military presence in Europe, the Washington Post stated citing a person familiar with the call.

During his election campaign, Trump promised to immediately settle the Ukrainian conflict but did not say how he was planning to do this. According to the newspaper, Trump said privately that he would support an agreement where Russia kept some of the liberated territories and during the phone call with Putin, he had briefly touched upon the issue of territories.

The US daily noted that the Ukrainian government was informed about the call and it did not object to it as the Kyiv officials understood that Trump would discuss the matter with Putin.

Putin’s press secretary Dmitry Peskov said on Friday that the Russian president is open to dialogue with Trump, however, in his words, nothing concrete could be said about it as of yet, Russian state media reported.

Also speaking at Thursday’s plenary session of the Valdai Discussion Club, Putin congratulated Trump on winning the presidential election, adding that he saw nothing wrong with calling Trump.

Trump, told NBC that he had not yet spoken with the Russian leader but believed such a call was highly likely.

On Sunday, US President Joe Biden’s National Security Advisor Jake Sullivan said the White House aims “to put Ukraine in the strongest possible position on the battlefield so that it is ultimately in the strongest possible position at the negotiating table.”

Sullivan also said on CBS News that President Biden and President-elect Trump will meet in the Oval Office on Wednesday.

“The first and most important message will be that President Biden is committed to the peaceful transfer of power and to a responsible handoff from one president to the next, which is in the best tradition of our country and has been for the last 240 years. And then they will go through the top issues, both domestic and foreign policy issues,” Sullivan told CBS News.

“Including what is happening in Europe and Asia and the Middle East. And the President will have the chance to explain to President Trump how he sees things, where they stand and and talk to President Trump about how President Trump is thinking about taking on these- these issues when he takes office,” the White House National Security advisor said.