The decision could endanger upcoming negotiations between Pyongyang and Washington, one Russian senator said.

Russia has slammed U.S. President Donald Trump's decision to withdraw from the Iran nuclear deal as a "flagrant violation" of international law.

"We are extremely concerned that the United States once again acts contrary to the position of most countries while pursuing solely its own narrow selfish and opportunistic interests," the Russian Foreign Ministry said.

The statement says that the unilateral decision undermines confidence in the international nuclear agencies that implemented and enforced the deal, and who had assured Iran was fully complying with its measures.

The head of Russia's International Affairs Committee, Leonid Slutsky, said that the move would create a "threat to international security," according to RT.

Russian Senator Andrey Klimov pointed out that the betrayal of the deal, which was the result of long negotiations, would harm any trust that North Korea could bring to upcoming negotiations between the United States and Pyongyang regarding denuclearization. A deal promising repealed sanctions and non-aggression in exchange for denuclearization could be discussed.

But the U.S. decision to withdraw from the nuclear deal may be a "signal particularly to Pyongyang: do not trust the United States," Klimov warned.

Russia, China, France and other countries party to the deal had urged Trump repeatedly to respect the agreement. Iran had warned that withdrawing from the deal would lead to further distrust.

Pulling out of the deal, Trump warned that powerful U.S. sanctions would be imposed if Iran engages in nuclear technology development. 

"It will have bigger problems than it has ever had before," Trump said. "Today's action sends a critical message: the United States no longer makes empty threats."

A poll by Reuters/Ipsos, conducted between May 4 and 8, revealed that only 29 percent of adults in the United States support the decision to withdraw from the deal. Even among those registered as members of Trump's Republican Party, less than half – 44 percent – advocated ending U.S. involvement in the agreement.

The same survey showed that around half of those polled were concerned the United States and Iran would enter into an armed conflict.