A group of Republican senators has sent a letter to Twitter chief executive Jack Dorsey, asking him to ban the accounts of Iranian Supreme Leader Ali Khamenei and the country’s Foreign Minister Mohammad Javad Zarif.

The letter was signed on Thursday by Ted Cruz, Marco Rubio, Tom Cotton and Marsha Blackburn, who are all known for sticking to a hardline stance on Iran.

The senators referred in the letter to an executive order signed by President Donald Trump last year which stipulates imposing sanctions on Khamenei and those acting on his behalf, something that they claimed prohibits Twitter from providing services to Khamenei and Zarif.

“While the First Amendment protects the free speech rights of Americans — and Twitter should not be censoring the political speech of Americans — the Ayatollah enjoys zero protection from the United States Bill of Rights,” the senators argued.

They accused Khamenei of being the “leader of the world's leading state sponsor of terrorism — directly responsible for the murder of hundreds of US citizens”, insisting that he and “any American companies providing him assistance are entirely subject to US sanctions laws”.

Despite an Obama administration-related provision exempting certain internet platforms from a spate of sanctions imposed on Iran, Khamenei and Zarif enjoy no such protection, according to the senators.

Even though “Twitter is aware of these accounts and their links to the Iranian regime”, it “continues to provide [them] with Internet-based communications services”, the senators noted, describing the situation as a “sanctionable offence”.

Twitter suspends major Iran news agency accounts

Twitter has not commented on the matter yet. While the social network removes accounts owned or directly affiliated with groups designated as foreign terrorist organisations by the State Department, it does not pursue a similar policy pertaining to those sanctioned by the Treasury Department.

In July, Twitter suspended the accounts of several major Iranian media outlets, including those of the official Islamic Republic News Agency (IRNA), the semi-official Mehr News agency and the Young Journalists Club (YJC).

The move followed the Iranian Revolutionary Guard Corps (IRGC) confiscating a UK-flagged tanker in the Strait of Hormuz after the vessel allegedly violated international regulations. Twitter made No statement explaining the decision.