On October 13, 2017, US President Donald Trump announced several measures designed to curb Iran’s support for terrorism and its pursuit of nuclear weapons. In his speech, the president noted that the Islamic Republic “provides assistance” to terrorist groups, including al-Qaida. Iran assisted al-Qaida operatives involved in the bombing of American embassies in Africa in the 1990s and even “harbored high-level terrorists in the wake of the 9/11 attacks,” he said. In fact, the evidence of Tehran’s ties to al-Qaida continues to grow.Trump is hardly alone in noting Iranian links to al-Qaida. Indeed, the bipartisan 9/11 Commission report stated that there was “strong evidence that Iran facilitated the transit of al-Qaida members into and out of Afghanistan before 9/11, and that some of these were future hijackers.” That same report highlighted a history of strategic cooperation between Iran and al-Qaida, beginning with discussions between Iranian operatives and Osama bin-Laden’s men in Sudan – which was then sheltering bin-Laden – in late 1991 or 1992.By the fall of 1993, al-Qaida terrorists were receiving training in explosives, intelligence and security tactics by elements of the Islamic Revolutionary Guard Corps (IRGC) in Lebanon’s Beqaa Valley.That cooperation was highlighted elsewhere, including in a December 22, 2011 US federal district court ruling, which held that “the Islamic Republic of Iran, its Supreme Leader Ayatollah Ali Hosseini Khamenei, former Iranian president Ali Akbar Hashemi Rafsanjani, and Iran’s agencies and instrumentalities, including, among others, the Iranian Revolutionary Guard Corps (IRGC), the Iranian Ministry of Intelligence and Security (MOIS), and Iran’s terrorist proxy Hezbollah, all materially aided and supported al-Qaida before and after 9/11,” according to a summary.In recent years, the US Treasury Department has repeatedly sanctioned several top al-Qaida operatives identified as living in Iran, including Ezedin Abdel Aziz Khalil, described by the agency in July 2011 as a “prominent Iranbased al-Qaida facilitator, operating under an agreement between al-Qaida and the Iranian government.”A new book by two British journalists, Cathy Scott-Clark and Adrian Levy, entitled The Exile: The Stunning Inside Story of Osama bin Laden and Al-Qaida in Flight, offers additional revelations about Iran’s cooperation with al-Qaida. Levy and Scott-Clark interviewed a number of senior al-Qaida operatives and bin-Laden family members, among others, including Mahfouz Ould al-Walid (aka Abu Hafs al-Mauritani), a senior al-Qaida adviser who was dispatched to Iran in December 2001 to negotiate sanctuary for members and families of the terrorist group in the wake of the US invasion of Afghanistan. Al-Walid would not emerge from Iran for more than a decade. What emerges from The Exile, however, is a damning indictment of the extent of Iranian support for al-Qaida.Al-Walid met with members of the Ansar ul-Mahdi Corps, an elite IRGC Quds Force unit, shortly after he arrived in Iran. Noting, “We have much in common,” including enemies like “USA and Israel,” the Iranians granted al-Qaida’s wish for sanctuary. In January 2002, this pledge was affirmed when “senior officials informed him that the highest authority – meaning [IRGC Quds Force head] General Qasem Soleimani – had approved al-Qaida’s safe haven.”By March 2002, the “al-Qaida exodus to Iran was at its height.” Some operatives and their families were granted stays in Tehran, including, at first, the four-star Howeyzeh Hotel. There, the men involved with planning and implementing the largest mass-murder in American history were provided with “room service, a ladies-only gym, movies and a swimming pool for the children.”The IRGC assisted with providing documentation and, Scott-Clark and Levy tell us, helped al-Qaida members escaping on flights, “some choosing to relocate to Muslim majority states in Southeast Asia, including Indonesia and Malaysia.” In other words: Iran helped spread al-Qaida terrorists throughout the globe.Much of al-Qaida’s top leadership, however, including its shura council and military chief, Saif al-Adel, stayed in Iran. There they were housed in various locations throughout the country – always under the watchful eye of the Quds Force, which often monitored their calls, placed listening devices in their houses and controlled their movements.The relationship between Tehran and al-Qaida in Iran was fraught with distrust and tension. Neither trusted the other. And early on at least, some members of Iran’s government disagreed with the Quds Force strategy of assisting and hosting al-Qaida. But the IRGC – with Supreme Leader Ali Khamenei’s support – won that debate, with the highest level’s of Iran’s government, including its Intelligence and Security Ministry, actively cooperating. Beyond providing shelter, Iran supported the group in other key ways.Al-Adel’s protégé, Abu Musab al-Zarqawi, “plotted to use [then] Iranian president [Mohammad] Khatami’s repatriation program to channel hundreds of al-Qaida fighters from Iran to Iraq.” Prior to the US invasion of Iraq, Tehran allowed al-Zarqawi to travel throughout the region, recruiting jihadists to take on coalition forces. Zarqawi was given real Iranian passports and communicated with a “Swiss satellite phone and two Iranian cell phones provided by the Quds Force.” He would go on to found al-Qaida in Iraq – the progenitor to the Islamic State in Iraq and Syria (ISIS).BASED IN Shiraz, Iran, al-Adel – who had extensive contacts with Iranian officials dating back to 1995 – plotted and communicated with al-Qaida members. By August 2007, al-Walid encountered al-Adel in “Block 300” near the Quds Force Training Facility in Tehran. With him were members of bin-Laden’s family and al-Qaida’s chief of foreign relations, Abu al-Khayr al-Masri, among others. For these at the top of the al-Qaida food chain, Soleimani “arranged shopping trips for the al-Qaida women,” furnished apartments with amenities, zoo trips – even gym memberships.“Once a week,” Levy and Scott-Clark note, “the families were taken to a sports complex in Elahieh, were Saif al-Adel, who had a $5 million bounty on his head, swam in lanes alongside foreign diplomats.” In 2007, bin-Laden’s sons broke the Eid fast with Soleimani as a dinner guest.Tensions between the hosts and their guests periodically rose and waned throughout the years, with bin-Laden son Sa’ad, among others, escaping Iran, only to be killed in a drone strike shortly thereafter. This didn’t stop tactical cooperation, however.In 2010, for example, Iran distributed anti-drone technology to al-Qaida allies, including the Haqqani network. It allowed financial coordination, assisted, the US Treasury Department noted in 2011 and 2015, by Qatari financiers. In September 2015, Iran acknowledged that it had “expelled” top members of Iran’s military council who were soon in Syria and “working alongside Soleimani.”More details on Iran’s support for al-Qaida can perhaps be found in the yet unreleased documents seized during the May 2, 2011 raid on bin-Laden’s compound. So far, the CIA has limited access by researchers and other intelligence officials to what has been described as a “library’s worth” of material. Those who were briefly allowed access, such as then-Defense Intelligence Agency (DIA) analyst Michael Pregent, commented, “We started seeing stuff that nobody was talking about, like Iranian facilitation of al-Qaida travel into Pakistan, for example.”A wider release of these documents will almost certainly provide more evidence of al-Qaida-Iran ties. One can’t count on Tehran to be forthcoming.The writer is a Washington, DC-based foreign-affairs analyst. The views presented in this article are his own.