MOSCOW -- The Kremlin warned Friday that a U.S. move against a nuclear deal with Iran would hurt global stability, while the Iranian parliament speaker said it would be an insult to the United Nations.

President Vladimir Putin's spokesman, Dmitry Peskov, said "such action would undoubtedly hurt the atmosphere of predictability, security, stability and non-proliferation in the entire world."

Peskov's comments were in response to a question about what the Kremlin reaction would be if the U.S. opts out of the deal. He spoke hours before U.S. President Donald Trump delivers a speech expected to contain harsh criticism of the 2015 nuclear accord.

Trump is expected to say the deal is no longer in U.S. national security interests, but he won't withdraw or immediately re-impose sanctions against Tehran, according to U.S. officials and outside advisers to the administration.

The agreement offered Iran relief from crippling economic sanctions in exchange for strict limits on its nuclear program. It was painstakingly negotiated by then-President Barack Obama's administration and involved a coalition of world powers including Britain, France, Germany, Russia and China.

Peskov said a U.S. move against the nuclear deal would have "very negative consequences" and "seriously exacerbate the situation around the Iranian nuclear dossier." He added that Iran has warned that it would respond by opting out of the deal.

Iranian parliament speaker Ali Larijani said on a visit to Russia that the accord has received a U.N. blessing, so any move to spike it would represent "primarily an insult to the U.N."

He added that any revision of the deal would allow Iran to take its own actions, and warned that a U.S. move could destabilize the international situation.

"We will continue to adhere to our obligations ... for as long as other parties observe the agreement," he said in remarks carried by Russian news agencies.