According to Arab News, the ban on arms sales to Iran was lifted under the terms of a UN resolution that approved a 2015 agreement between Tehran and world powers.
Iran can now buy weapons from Russia, China and anywhere. Tehran has called the lifting of the arms embargo a diplomatic success.
However, US Secretary of State Mike Pompeo said on Sunday that arms sales to Iran would still be in violation of UN resolutions and would result in sanctions.
Mike Pompeo added that US authorities could ban any individual or entity that buys or sells conventional weapons to or from Iran.
He said that any nation that wants peace in the Middle East and supports the war on terror should refrain from buying and selling arms.
He said that for the past 10 years, various countries have been refraining from buying and selling arms to Iran under various UN resolutions. Any country that challenges this will clearly choose to promote conflict and tension rather than peace and security.
Dr. Majid Rafizadeh, an Iranian-American Howard scholar, told Arab News that lifting the arms embargo is a major threat to regional and international stability.
"Allowing the world's worst terrorist-sponsoring country to possess unlimited conventional weapons will be remembered in history as a dangerous opportunity to disrupt world peace."
"The beneficiaries are Revolutionary Islam, its proxies and armed groups in the region," he said. The latest weapons could come from Syrian dictator Bashar al-Assad, Iranian terrorists and armed groups such as the Houthis, Hezbollah, Hamas and Iranian-backed armed groups in Iraq.
Security analyst Dr. Theodore Kirasak says Iran first obtained technical data from other countries for its weapons capability.
According to Dr. Theodore Kerask, Tehran's weapons engineering and reverse engineering means that Iran will potentially buy small arms, such as Cornet anti-tank missiles from Russia, and acquire a Chinese optical jammer against drone strikes.
"Iran wants to acquire the Russian S400 air defense and coastal defense system Baston," he said. China will also benefit. It is thought that Iran will buy the anti-ship cruise missile C-802 and possibly take naval control craft from China.
