Russia on Monday warned that there would be “negative consequences” if United States President Donald Trump decides to pull out of the Iran nuclear deal, AFP reported. “Obviously if one country leaves the deal, especially such a key country as the US, then that will have negative consequences,” said Russian President Vladimir Putin’s spokesperson Dmitry Peskov. “We can only try to predict the nature of these consequences, which we are doing now.”

Trump is expected to decertify the nuclear deal with Iran on October 15. Trump’s action will not immediately pull the US out of the agreement, but will give the Congress 60 days to decide whether to reimpose sanctions on Iran, which existed prior to the deal.

Iran Deputy Foreign Minister Majid Takht-Ravanchi on Monday said Tehran was ready to face the “worst scenarios” if Trump decertifies the deal, reported the Tehran Times. He added that the United States would be globally isolated if it pulls out of the deal.

Trump is also expected to designate Iran’s top security force, the Islamic Revolutionary Guards Corp, as a terrorist group. On Monday, Tehran condemned Trump’s planned move. “We are hopeful that the United States does not make this strategic mistake,” Iran’s Foreign Ministry spokesperson Bahram Qasemi, said according to the country’s Islamic Republic News Agency.