Iran's Araqchi says he is going to Moscow for a meeting with Putin on Monday

"I'm going to Moscow this afternoon, and I have a meeting with President Putin tomorrow morning. Russia is a friend of Iran," Iran's Foreign Minister told reporters in Istanbul.

Earlier, Dmitry Medvedev, the deputy chairman of Russia's Security Council, wrote on his Telegram channel: "Trump, who came in as a peacemaker president, has started a new war for the U.S."

Asked what kind of damage had been incurred on the nuclear facilities, Araqchi said: "I still do not have exact information about the level of damages".

"The United States showed that they have no respect to United Nations Charter. They have no respect to international law," he added. "They crossed a very big red line by attacking nuclear facilities."

"I'm not in a position to reveal what we are going to do in response to what Americans did last night," he said.

Speaking in Istanbul, Abbas Araqchi said Iran strongly condemned U.S. attacks as a "violation of international law".

"The US administration holds sole and full responsibility for the consequences of its actions, including the Islamic Republic of Iran's right to self-defense," he said.

"Of course, the door for diplomacy should always be kept open. But this is not the case right now. My country has been under attack, under aggression, and we have to respond based on our legitimate right of self-defense."