WASHINGTON -- US President Donald Trump said Friday that the United States is holding "very good" talks with Russia and Ukraine, expecting "something could be happening" on resolving the conflict, which is approaching its fourth year.

"We have very good talks going with Russia and Ukraine," Trump told reporters aboard Air Force One. "Something could be happening."

The president provided no further details.

The second round of the US-brokered talks between Russia and Ukraine concluded in Abu Dhabi on Thursday, with both sides agreeing to a large-scale prisoner exchange but failing to achieve substantive breakthroughs on core issues such as territorial arrangements.

Ukrainian President Volodymyr Zelensky said Thursday that the next peace talks with the US and Russian delegations will be held "in the near future, likely in the United States."