"While religious terrorism is concerning, the United States does not face the same level of threat today from religious extremists—particularly those inspired by Salafi-jihadist groups such as the Islamic State and al-Qaeda—as some European countries. But Salafi-jihadists still pose a limited threat. In December 2019, Second Lieutenant Mohammed Saeed Alshamrani, a Saudi air force cadet training with the American military in Pensacola, Florida, killed three men and injured three others. He was inspired by al-Qaeda’s ideology, communicated with leaders of al-Qaeda in the Arabian Peninsula up until the attack, and joined the Saudi military in part to carry out a “special operation.” In addition, leaders of al-Qaeda and the Islamic State continue to encourage individuals in the West—including the United States—to conduct attacks. There are still perhaps 20,000 to 25,000 jihadist fighters in Syria and Iraq from the Islamic State and another 15,000 to 20,000 fighters from two al-Qaeda-linked groups: Hay’at Tahrir al-Sham and Tanzim Hurras al-Din. Over the next several months, more jihadists may enter the battlefield after escaping—or being released—from prisons run by the Syrian Democratic Forces in areas such as al-Hol, located in eastern Syria near the border with Iraq. In addition, there are still concerns about al-Qaeda and Islamic State groups operating in Yemen, Nigeria and neighboring countries, Somalia, Afghanistan, and other countries. In a May 2020 report, the United Nations concluded that al-Qaeda remains a serious threat and that the “senior leadership of Al-Qaida remains present in Afghanistan, as well as hundreds of armed operatives, Al-Qaida in the Indian Subcontinent, and groups of foreign terrorist fighters aligned with the Taliban.”"