US President Donald Trump says he will be speaking to Russian President Vladimir Putin by phone about the conflict in Ukraine.

Trump posted on social media on Saturday that his conversation with Putin will be held on Monday.

He said that afterwards, he will speak to Ukrainian President Volodymyr Zelenskyy and various NATO member countries.

Trump apparently aims to make a breakthrough toward a ceasefire by holding summit talks. He wrote, "HOPEFULLY IT WILL BE A PRODUCTIVE DAY, A CEASEFIRE WILL TAKE PLACE, AND THIS VERY VIOLENT WAR, A WAR THAT SHOULD HAVE NEVER HAPPENED, WILL END."

The announcement comes after senior officials from Russia and Ukraine held direct talks on Friday for the first time in more than three years. But the meeting highlighted wide gaps still remaining between the two sides.

Trump earlier said that nothing is going to happen until he and Putin speak directly.

Russia's presidential spokesperson Dmitry Peskov has confirmed to local media that preparations are underway for the conversation.