President Vladimir V. Putin of Russia warned the United States late Thursday against sending powerful cruise missiles to Ukraine. But he quickly added that he did not expect such deliveries to happen, in the latest sign that the Russian leader is continuing to bet that he can keep a warm relationship with President Trump even while frustrating his ambitions to end the war.

Vice President JD Vance said on Sunday that Mr. Trump might agree to sell American-made Tomahawk cruise missiles to European countries that would send them to Ukraine. President Volodymyr Zelensky has argued that Ukraine needs more powerful long-range weapons to deter Russian aggression, and reiterated the request at his meeting with Mr. Trump in New York last month.

Mr. Putin, in an annual appearance at a Russian foreign-policy conference on Thursday, sought to project confidence that, in the end, Mr. Trump would decide against providing the missiles to Ukraine. He described the American president as someone who “loves to shock a little” but who also “knows how to listen.”

If the United States did send Tomahawk missiles to Ukraine, Mr. Putin said, the move would bring about “a qualitatively new stage of escalation.” But he went on to predict that Mr. Trump would eventually reject Ukraine’s request in part because of the United States’ inward turn under the Trump administration.

“What I see is that, as of today, the U.S. leadership is still inclined to pursue a different policy,” Mr. Putin said, “focusing on achieving national development goals, as they understand them.”

A Tomahawk has a range of 1,500 miles, more than seven times the range of the American missile systems called ATACMS that Ukraine got last year. But the Tomahawk is also a technically complex weapons system that the U.S. military needs to retain for its own uses, and analysts in Ukraine and in the West also doubt that the Trump administration would agree to provide the missiles.