US President Donald Trump and Russian President Vladimir Putin have spoken about “immediately” starting negotiations to end the war in Ukraine.

The two leaders spoke for nearly 90 minutes in the first known phone call between the pair since Trump took office in January.

Both sides confirmed some details of the chat, which covered a range of topics including agreeing to meet in person and an invitation for Trump to visit Moscow.

Trump revealed on Thursday (AEDT) that they had discussed ending the three-year war between Russia and Ukraine.

“We have also agreed to have our respective teams start negotiations immediately,” he wrote on social media.

“We will begin by calling President [Volodymyr] Zelensky, of Ukraine, to inform him of the conversation, something which I will be doing right now.

“Millions of people have died in a War that would not have happened if I were President, but it did happen, so it must end. No more lives should be lost!”

The Kremlin said the two men had agreed to meet.

“The Russian president invited the US President to visit Moscow and expressed his readiness to receive American officials in Russia in those areas of mutual interest, including, of course, the topic of the Ukrainian settlement,” Kremlin spokesman Dmitry Peskov said.

“Putin and Trump also agreed to continue personal contacts, including arranging a face-to-face meeting.”

Afterwards, Trump posted that he had also spoken to Zelensky and the “conversation went well”.

“He, like President Putin, wants to make PEACE,” posted Trump.

“It is time to stop this ridiculous War, where there has been massive, and totally unnecessary, DEATH and DESTRUCTION. God bless the people of Russia and Ukraine!”

Zelensky is due to meet US Vice President JD Vance and Secretary of State Marco Rubio in Munich on Friday (local time).

Trump has long said he would quickly end the war in Ukraine, without saying how he would accomplish this.

Earlier, Trump’s Defence Secretary, Pete Hegseth, said a return to Ukraine’s pre-2014 borders was unrealistic and the US administration did not view NATO membership for Ukraine as part of a solution to the war.

Speaking at a meeting of Ukraine’s allies at the headquarters of the NATO military alliance in Brussels on Wednesday, Hegseth delivered the clearest and bluntest public statement so far on the new US administration’s approach to the nearly three-year-old war.

“We want, like you, a sovereign and prosperous Ukraine. But we must start by recognising that returning to Ukraine’s pre-2014 borders is an unrealistic objective,” Hegseth told a meeting of Ukraine and more than 40 allies at NATO headquarters in Brussels.

“Chasing this illusionary goal will only prolong the war and cause more suffering.”

-with DPA/AAP