US President-elect Donald Trump held his first phone call with Russian President Vladimir Putin on November 7 and warned Moscow “not to escalate the war in Ukraine”, the Washington Post reports.

Trump reminded Putin of Washington’s “sizable military presence in Europe,” according to sources cited by The Washington Post. The call broke diplomatic protocol, as it was not scheduled by the US State Department officials, and took place unsupervised and without government interpreters, adding to concerns about Trump’s unpredictable and impulsive ruling style.

Trump’s team confirmed to CNBC that since his victory over Vice President Kamala Harris on November 5, the president-elect has spoken with approximately 70 world leaders, including Putin.

The call with Putin was reportedly arranged through informal channels. Putin did not publicly congratulate Trump on his victory, but Russian outlet Verstka reported that Putin had sent his congratulations “indirectly through acquaintances” rather than a formal call.

Kremlin spokesperson Dmitry Peskov earlier stated that he was “not aware” of plans by Putin to congratulate Trump, as the United States remains an “unfriendly country involved in a war against Russia.”

The reaction from Kyiv has been mixed. Ukrainian officials were informed of the call in advance, The Washington Post reported, noting that officials “did not object to the conversation taking place.” “Subsequently, Ukraine could not have endorsed or opposed the call,” Foreign Ministry spokesperson Heorhii Tykhyi told reporters on November 10.

Trump has previously enjoyed good relations with Putin and is known to admire strong leaders. But Trump also threatened to stop the war in 24 hours after taking office. Putin commented on Trump’s outreach, stating: “What [Trump] said in terms of seeking to restore relations with Russia, to help bring the ‘Ukrainian crisis’ to an end, I think is noteworthy at least.”

Ominously, Trump’s son, Donald Trump junior, released a tweet showing Ukrainian President Volodymyr Zelenskiy and with the caption: “POV: You’re 38 days from losing your allowance,” in what was taken as a reference to Trump’s inauguration on January 20. The tweet fuelled speculation that the US will drastically reduce its financial support for Ukraine once Trump takes office.

The phone will also fuel speculation that ceasefire talks between Russia and Ukraine are likely to start soon, as Ukraine fatigue amongst Ukraine’s allies is palpable.

Polish Prime Minister Donald Tusk said at the weekend that key announcements on a potential ceasefire in Ukraine, the expected border of control and security guarantees for Kyiv are anticipated in the “near future.”

Tusk said the decisions on the conflict would likely entail “less US interference in Ukrainian affairs,” suggesting a shift in Washington’s approach under the incoming administration to put more of the burden on Europe.

Speaking on the broader implications, he cautioned that the fate of Ukraine “can neither be decided over the heads of Ukrainians nor over ours.”