The elite Iranian force believed to be protecting Saad bin Laden and two dozen al Qaeda leaders is one of the Islamic Revolutionary Guard Corps' five branches, and has been given the mission of "exporting the Islamic revolution" by training, arming and collaborating with foreign terrorist groups -- even those that do not share Iran's fundamentalist Shiite brand of Islam.

The Jerusalem Force, also known as the Qods Force, is highly trained and well-funded. It has provided instruction to more than three dozen Shiite and Sunni "foreign Islamic militant groups in paramilitary, guerrilla and terrorism" tactics, according to a recent U.S. intelligence analysis.

Groups including Hezbollah, or Party of God; the Islamic Resistance Movement (Hamas); and Palestinian Islamic Jihad have received arms and training at one of several specialized sites in Iran, according to that document.

The Jerusalem Force's former commander, Ahmad Vahidi, allegedly helped plan the 1994 bombing of the Amia Jewish Center in Buenos Aires, in which 85 civilians were killed and 230 injured, according to Argentine intelligence officials and others.

The group has also maintained ties with the al Qaeda terrorist network for more than a decade, according to U.S. and European intelligence officials. Senior al Qaeda leaders first met and formed a tactical alliance with the nascent Jerusalem Force in Sudan in the early 1990s, according to intelligence officials. The group was creating terrorist training camps there at the same time that Osama bin Laden had begun to create his own financial and training infrastructure.

Bin Laden's second-in-command, Ayman Zawahiri, used his decade-old relationship with Vahidi, then commander of the Jerusalem Force, to negotiate a safe harbor for some of al Qaeda's leaders who were trapped in the mountains of Tora Bora, Afghanistan, in 2001, according to a European intelligence official.

The group is "a state within a state, and that is why they are able to offer protection to al Qaeda," one European intelligence analyst said. "The Force's senior leaders have long-standing ties to al Qaeda, and, since the fall of Afghanistan, have provided some al Qaeda leaders with travel documents and safe haven."

The organization's autonomy from Iran's elected leaders underscores the deep split between the moderate government of President Mohammad Khatami and the unelected hard-line clerics who control much of the nation's security apparatus.

Khatami, who has repeatedly denied that senior al Qaeda figures are in Iran, has no control over security organs such as the Revolutionary Guard, which answer to the office of the supreme religious leader, Ayatollah Ali Khamenei.

Although Iran is a Shiite Muslim nation, the Jerusalem Force's willingness to work with rival Sunni Muslim organizations has made it particularly dangerous as a liaison between Iran and other Islamic groups that share its goal of destroying secular Muslim states.

The Jerusalem Force has agents in "most countries with substantial Muslim populations," according to the U.S. analysis. "Their mission is to form relationships with Islamic militant and radical groups and offer financial support either to the groups at large or to Islamic figures within them who are sympathetic to the principles and foreign policy goals of the Iranian government."

The Force's training regime includes psychological and guerrilla warfare operations, with emphasis on the use of hand grenades, mines, booby-trap techniques, camouflage and ambushes. Its terrorist-related training includes assassinations, kidnapping, torture and explosives, according to the U.S. intelligence analysis.