The "9/11 Commission Report" stated that 8 to 10 of the 14 Saudi hijackers on 9/11 had passed through Iran and their travel was facilitated by Iranian border guards. Ramzi bin al-Shibh and Khalid Sheikh Mohammed , the principal architect of 9/11, attested that several of the 9/11 hijackers transited through Iran taking advantage of the Iranian practice of not stamping Saudi passports.They denied any other reason for the hijackers’ travel to Iran as well as any relationship between the hijackers and Hezbollah. The report found that Iranian officials issued specific instructions to the border guards to facilitate the travel of 9/11 hijackers. lt also found "circumstantial evidence that senior Hezbollah operatives were closely tracking the travel of some of these future muscle hijackers into Iran in November 2000."