The end of the United Nations arms embargo against Iran on October 18, 2020 is expected to bring about a new era of heavy arms competition between the United States and Russia. The absence of an embargo opens up opportunities for Iran to be able to buy and market weapons from and to the country. The United Nations has previously rejected a US proposal to extend the embargo on Iran. Iran's Ministry of Foreign Affairs declared Iran's independence in the field of defense shortly after the arms embargo ended.

One possibility that will happen is, Tehran will move closer to Moscow to cooperate in the field of advanced air defense. This is in line with the statement of the Russian Foreign Ministry through Levan Jagarian, Russia's Ambassador to Iran. He told an Iranian newspaper that most likely his country would sell S400 air defense system to Iran. The Russian ambassador's remarks appeared to be a response to Washington's warning against taking steps that could cause new tensions. The Russian Ambassador in Tehran firmly stated that Russia was not afraid of the threat of the United States.

A number of mass media in Russia have written news about the sophistication of the country's S400 air defense system. It is reported that the development has used a new generation digital processor, capable of detecting radar frequencies as well as a sophisticated computerized system. It is even believed that the latest variant of the S400 can destroy US-made fifth-generation stealth fighters and even B-2 bombers. The issue of the planned sale of this advanced air defense system to Iran, suggests that Russia is likely to want to test the S400 through Tehran's hands.

In this perspective, the end of the UN arms embargo on Iran could trigger an escalation in competition for modern heavy weapons, especially weapons for air strikes and defense between countries, in this case the United States and Russia. However, the issue that Iran will realize the purchase of S 400 air defense weapons still needs proof. It seems that the Iranian government still has to take careful steps by considering the so-called Iranian defense doctrine. Based on this doctrine, decisions regarding defense matters are very dependent on the people. This includes preventing steps that are considered extravagance in buying weapons from abroad.