DUBAI, May 21 (Reuters) - Iran's foreign minister, Mohammad Javad Zarif, advised U.S. President Donald Trump to discuss how to avoid another September 11 attack with the Saudi hosts of his first official visit abroad, Zarif wrote in an editorial published on Sunday.
Tehran and Riyadh are regional arch-rivals who accuse each other of sponsoring fundamentalist militias aligned to their competing sects of Islam in warzones across the Middle East.
Critics of Saudi Arabia say its strict view of Islam fuels Sunni extremism, called takfir, and some even accuse the kingdom of responsibility for the September 11 attacks.
Saudi Arabia denies providing any support for the 19 hijackers - most of whom were Saudi citizens - who killed nearly 3,000 people in 2001.
"(Trump) must enter into dialogue with them about ways to prevent terrorists and takfiris from continuing to fuel the fire in the region and repeating the likes of the September 11 incident by their sponsors in Western countries," Zarif wrote for the website of the London-based Al Araby Al-Jadeed news network.
At a campaign event last February, Trump himself suggested to supporters that the kingdom may be behind the attacks.
"You will find out who really knocked down the World Trade Center because they have papers out there that are very secret. You may find it's the Saudis, okay, but you will find out."
But since his election, Trump has put an end to his sharp commentary in public and on his twitter account about the key U.S. ally and the world's top oil exporter.
On the second day of his visit to Riyadh, the president is set to deliver an appeal to leaders from across the Arab and Muslim world to unite against the common threat posed by Islamist militants. (Reporting by Noah Browning; Editing by Elaine Hardcastle)