The war began three years ago when Moscow invaded its neighbor. In response the U.S. and its NATO allies have sent billions of dollars in military aid and other support to Kyiv.
Trump said he and Putin agreed to work closely together and visit each other's nations.
"I just had a lengthy and highly productive phone call with President Vladimir Putin of Russia. We discussed Ukraine, the Middle East, Energy, Artificial Intelligence, the power of the Dollar, and various other subjects," he said.