Russian officials continue to criticize U.S. policy towards Iran, especially new sanctions to be announced Monday by Washington.

Kremlin spokesman Dmitry Peskov called U.S. sanction “unlawful” Monday, and Russian Deputy Foreign Minister Sergei Ryabkov said tightening of sanctions leads to further escalation of tensions.

"The fact that the Americans are threatening to impose new sanctions and are likely to do so is a reflection of the deliberate and purposeful escalation policy," Ryabkov said.

The United States announced over the weekend that new sanctions will be soon announced against Tehran, after Iranian forces shot down a U.S. drone on June 20.

Referring to U.S. economic sanctions against Iran, Ryabkov said, “All these actions are totally counterproductive and dangerous”, adding, “No doubt, we condemn such U.S. policy and have repeatedly declared illegality of unilateral sanctions”.

President Donald Trump and senior administration officials have been offering “unconditional talks” with Iran in recent weeks, but Iran’s Supreme Leader Ali Khamenei has shut the door to any negotiations with Washington.

Ryabkov also singled out the U.S. offer of talks as “nothing but declarations”, saying, “there have been no definite proposals regarding topics of this dialogue besides what Trump said and what the state secretary and representatives of the Department of State said quite harshly in furtherance”.