U.S. President Donald Trump on Wednesday suggested new sanctions could be imposed on Russia if it fails to agree to a Ukraine peace deal, warning “you’ll see things happen” if he is not satisfied with President Vladimir Putin’s response.

"Whatever his decision is, we'll either be happy about it or unhappy. And if we're unhappy about it, you'll see things happen," Trump told reporters in the Oval Office as he met Polish President Karol Nawrocki.

Trump also said Wednesday that he will soon "find out" just how good his relationships are with the leaders of China, India and Russia after the leaders attended a key ceremony.

Trump said a ceremony hosted by China to commemorate the 80th anniversary of the end of World War II, attended by Russian President Vladimir Putin and Indian Prime Minister Narendra Modi, was "beautiful" and "very, very impressive," but suggested the US was intentionally slighted.

"I understood the reason they were doing it, and they were hoping I was watching, and I was watching. My relationship with all of them is very good," he told reporters as he hosted Polish President Karol Nawrocki.