President Donald Trump is hoping that separate phone calls Monday with Russian leader Vladimir Putin and Ukrainian President Volodymyr Zelensky will make progress toward a ceasefire in the war in Ukraine.

Axar.az, citing AP, reports that Trump expressed his hopes for a “productive day” on Monday—and a ceasefire—in a social media post over the weekend. His effort will also include calls to NATO leaders.

Kremlin spokesman Dmitry Peskov confirmed to the media on Monday that Putin and Trump will speak at 5 p.m. Moscow time (1400 GMT).

Trump has struggled to end a war that began with Russia’s invasion in February 2022, and that makes these conversations a serious test of his reputation as a dealmaker after having claimed he would quickly settle the conflict once he was back in the White House, if not even before he took office.