Sending a tough message to Tehran shortly after pragmatist Hassan Rouhani was re-elected president, U.S. President Donald Trump urged Arab leaders to unite to defeat militants, and said Iran had for decades "fueled the fires of sectarian conflict and terror." Trump's choice of Saudi Arabia, Iran's bitter regional rival, for his first official foreign visit reflects the deep antagonism of his administration towards Iran.

Iran's ruling powers represent the "tip of the spear" of global terrorism, Saudi King Salman bin Abdulaziz Al Saud said in a speech on Sunday during Trump's visit to the kingdom. "Our responsibility before God and our people and the whole world is to stand united to fight the forces of evil and extremism wherever they are ... The Iranian regime represents the tip of the spear of global terrorism," he said.

The U.S. president signed a giant list of deals, worth a total of $380 billion, including $110 billion for weapons that will invariably find their way into the numerous conflicts of the region — including Syria, Yemen and Iraq — where Riyadh and Tehran often find themselves on opposing sides.

Iran accused the U.S. yesterday of spreading "Iranophobia" to encourage Arab states to purchase arms, state TV reported.

"Once again, by his repetitive and baseless claims about Iran, the American president ... tried to encourage the countries of the region to purchase more arms by spreading Iranophobia," Foreign Ministry spokesman Bahram Qassemi said, a day after President Trump ended a visit to Tehran's arch-foe Saudi Arabia, where arms deals worth almost $110 billion were signed.

He said the U.S. and its allies "should know that Iran is a democratic, stable and powerful country" and that it promoted "peace, good neighborliness, and the creation of a world opposed to violence and extremism."

Iran's foreign minister, Mohammad Javad Zarif, advised Trump to discuss how to avoid another Sept. 11 attack with the Saudi hosts of his first official visit abroad, Zarif wrote in an editorial published on Sunday.

Iran, which has been accused of exposing sectarian fault lines in the region, especially in Yemen, Syria and Iraq, tried to soften its rhetoric as Rouhani said there should be greater unity between Shiites and Sunnis and that they had coexisted side by side peacefully for hundreds of years. During the Barack Obama era, Iran enjoyed the opportunity to fill the vacuum in the Middle East after the White House abandoned its traditional allies, like Turkey and Saudi Arabia.

The Iranian president championed a nuclear deal with the United States and five other major powers in 2015 that led to the lifting of most sanctions against Iran last year in return for curbs on its nuclear program. Gulf Arab states expressed support for the deal, but also fears that the lifting of sanctions would enable Tehran to pursue destabilizing policies in the Middle East.