According to a Ukrainian military source, Russia and Ukraine initiated a significant prisoner exchange on Friday, marking their first direct negotiations in over three years.

President Donald Trump announced the completion of the prisoner swap, though official confirmations from Kyiv and Moscow were absent, and the military source indicated the exchange was still in progress.

Last week, during two hours of discussions in Istanbul, Russia and Ukraine consented to the exchange of 1,000 prisoners but could not finalize a ceasefire suggested by Trump. In the past, the United Arab Emirates has played a mediating role in prisoner swaps.

The prisoner swap was the only concrete step towards peace the two sides agreed at their talks in Istanbul.

“Congratulations to both sides on this negotiation. This could lead to something big???,” Trump said in a post on Truth Social.

Hundreds of thousands of soldiers on both sides are believed to have been wounded or killed in Europe’s deadliest war since World War II, although neither side publishes accurate casualty figures. Tens of thousands of Ukrainian civilians have also died as Russian forces have besieged and bombarded Ukrainian cities.

Ukraine says it is ready for a 30-day ceasefire immediately, but Russia, which launched the war by invading its neighbor in 2022 and now occupies about a fifth of Ukraine, says it will not pause its assaults until conditions are met first. A member of the Ukrainian delegation called those conditions “non-starters”.

Trump, who has shifted U.S. policy from supporting Ukraine towards accepting some of Russia’s account of the war, had said he could tighten sanctions on Russia if Moscow blocked a peace deal. But after speaking to Putin on Monday he decided to take no action for now.

Moscow says it is ready for peace talks while the fighting goes on, and wants to discuss what it calls the war’s “root causes,” including its demands Ukraine cede more territory, and be disarmed and barred from military alliances with the West.

Kyiv says that is tantamount to surrender and would leave it defenseless in the face of future Russian attacks.