Moscow: After five years of grinding conflict stoked by Russia in eastern Ukraine, the two bitterly estranged neighbours swapped dozens of prisoners on Saturday in a long-anticipated exchange that Ukraine's new president hailed as "the first step to ending the war".

Welcoming 35 freed Ukrainians at the airport in Kiev, President Volodymyr Zelensky, a former comedian, said he had spoken by telephone with Russia's President Vladimir Putin and reached an agreement "on the first stage to unblock our dialogue".

Chancellor Angela Merkel of Germany welcomed the exchange as a "hopeful sign." Merkel has been deeply involved in the so far fruitless efforts to stop the fighting, which has killed more than 13,000 people, many of them civilians.

US President Donald Trump said on Twitter that the exchange was "very good news, perhaps a first giant step to peace." Donald Tusk, the European Council President, said of the release, "Finally!"