The Kremlin on Monday rejected reports that President Vladimir Putin spoke last week with President-elect Donald Trump about the war in Ukraine, and a spokesman for Trump refused to comment on what he called his "private calls" with world leaders.

The Washington Post first reported on Sunday, citing anonymous sources, that the two spoke on Thursday, with Trump advising Putin not to escalate the war in Ukraine and cited the sizable U.S. military presence in Europe.

In a conference call Monday with journalists, Kremlin press secretary Dmitry Peskov said "there was no conversation" and the report was "completely untrue, it is pure fiction."

Asked about the report, Trump's communications director Steven Cheung said, "We do not comment on private calls between President Trump and other world leaders."

Speaking at a foreign policy forum Thursday in Russia's Black Sea resort of Sochi, Putin offered congratulations to Trump on his election victory and praised him for what he said was "brave" behavior during an assassination attempt on him in July.

Peskov said "there are no specific plans yet" for a conversation between Putin and Trump. He said previously that contacts between the two before Trump's inauguration "are not ruled out" and pointed to Trump saying that he would call Putin before the inauguration. He denied, however, that Russia's presidential administration or Foreign Ministry had any contacts with Trump's campaign after the election.

During his campaign, Trump repeatedly said he could quickly end the fighting in Ukraine but did not offer details of how he would accomplish that.

Russia has intensified strikes on civilian areas in Ukraine as the war approaches its 1,000-day mark. For its part, Ukraine over the weekend sent a massive wave of drones that rattled Moscow and its suburbs.