U.S. President Donald Trump on Thursday pressed Russia to accept a 30-day unconditional ceasefire with Ukraine, with any breaches punishable by sanctions.

Trump renewed the pitch for a truce after speaking to Ukrainian President Volodymyr Zelenskyy, who has moved to shore up his relationship with the U.S. administration after a bitter White House clash on Feb. 28.

"Talks with Russia/Ukraine continue. The U.S. calls for, ideally, a 30-day unconditional ceasefire," Trump said on his Truth Social network after speaking to Zelenskyy.