In defense of his administration’s decision to assassinate Qassem Suleimani, Mike Pence has been promoting conspiracy theories that link September 11 terrorists to Iran.

In a series of tweets, the US vice-president called Suleimani “an evil man who was responsible for killing thousands of Americans”. Among other things, Pence insisted that the general “assisted in the clandestine travel to Afghanistan of 10 of the 12 terrorists who carried out the September 11 terrorist attacks in the United States”, misstating the number of 9/11 hijackers – there were 19 – and insinuating Suleimani’s involvement despite a lack of evidence.

Foreign policy experts were quick to point out on social media that Pence’s assertions were unsubstantiated.

The official 9/11 commission report found there was “no evidence that Iran or Hezbollah was aware of the planning for what later became the 9/11 attack”, and that 15 out of the 19 hijackers were from Saudi Arabia, and the remainder were from the United Arab Emirates, Lebanon and Egypt. Moreover, Suleimani’s name is never mentioned in the nearly 600-page report.

Experts have also pointed out that Suleimani, a Shia leader, would have been an unlikely ally to the Sunni militants that carried out the attacks. This isn’t the first time that the Trump administration and supporters have promoted a link between al-Qaida – the group that launched the 9/11 attack – and Iran. Insisting that these groups are in cahoots could be key in legally justifying a war against Iran.

A 2001 law allows the president “to use all necessary and appropriate force against those nations, organizations, or persons he determines planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons” – without waiting for congressional approval.

Though Iran, and its proxy group Hezbollah in Lebanon, has cooperated with al-Qaida before, both the 9/11 commission report and a 2018 study by the New America thinktank, based on roughly 470,000 declassified files found that the groups didn’t work together to commit terrorist acts.

Despite criticism from policy experts, Pence’s press secretary, Kate Walderman, later reiterated the claim that Suleimani somehow assisted the 9/11 hijackers, but did not offer evidence.