U.S. President Donald Trump's envoy for the Ukraine conflict met President Volodymyr Zelenskiy in Kyiv on Thursday but there was no immediate word on whether their talks had helped smooth over an unprecedented wartime rift between the once firm allies, and key U.S. officials indicated that major frustrations remain.

The Trump administration had earlier announced it had agreed to hold additional talks with Russia to end the nearly three-year-long conflict, following a 4.5-hour meeting in Saudi Arabia.

Ukrainian service members of the 68th Jaeger Brigade named after Oleksa Dovbush attend military exercises at a training ground, amid Russia's attack on Ukraine, in Dnipropetrovsk region, Ukraine February 20,