Iran continues to increase its influence in the Middle East region and remains the main state sponsor of terrorism, Director of the Central Intelligence Agency (CIA) Mike Pompeo said.
He added that the spread of the Iranian influence may become the greatest challenge for the United States' Middle East policy in the long term.
"The Islamic Republic of Iran is a powerful nation state that remains the world's largest state sponsor of terrorism.
Its strength and influence continue to increase, most notably in recent years.
When we look at what is happening today in Syria, in Yemen and in Iraq, you can see the threat.
Iran clearly inspires to be the hegemonic power in the region," Pompeo said on Tuesday.
Iran managed to escape the international isolation in 2015 when the country signed the Joint Comprehensive Plan of Action that came into force in January 2016.
The deal between Iran and the P5+1 countries, namely China, France, Russia, the United Kingdom, the United States plus Germany, stipulated the limitation of Tehran's nuclear program in exchange for the gradual lifting of international economic and diplomatic sanctions imposed on Iran.