After a decade in which al Qaeda dominated the world stage, the global terror threat from Iran has escalated sharply, generating a swarm of recent plots from Delhi to Mombasa to Washington and signaling an aggressive new strategy, counterterror officials say.
But there were meager results until this month. On July 18, a suspected suicide bomber killed six people and wounded 30 aboard an Israeli tourist bus in a coastal town in Bulgaria. Israel quickly accused Hezbollah and Iran, longtime sponsor of the Lebanese Shiite militant group. Many questions remain about the bombing, and Bulgarian authorities have said they do not have proof implicating Hezbollah so far. Nonetheless, many Western counterterror officials share Israel's suspicions.
If the allegations are true, Iran and Hezbollah have crossed a dangerous line with their first strike in Europe in more than 15 years. The repercussions are stoking more turmoil in a Middle East torn by civil war in Syria and conflict over Iran's nuclear ambitions.
ProPublica has reviewed a string of plots attributed to the Shiite alliance, 10 cases in the past year alone, and found a complex and contradictory evolution of the threat. Iran and Hezbollah have waged a determined campaign to strike their enemies in retaliation for attacks on the Iranian nuclear program and the killing of a Hezbollah chief, counterterror officials say. The offensive led by the Quds Force, Iran's elite foreign operations unit, has displayed impressive reach and devastating potential.
"The Hezbollah-Quds force threat is the big thing worldwide right now," a U.S. counterterror official said. "There has been a wave of activity."
Yet the modus operandi so far has veered between agility and clumsiness, precision and improvisation. Most of the attempted strikes have failed, often hampered by hasty execution and unreliable operatives, according to counterterror officials and experts around the world. In some ways the apparent opportunism and erratic behavior make the menace worse, increasing the chances of conflict with the West, experts say.
"These cases all seem amateurish," an Indian counterterror official said. "The Iranians feel great frustration and desperation because of the attacks on the nuclear program, a real desire to strike. So they aren't prepared 2014 they act quickly. They don't care about reprisals. They are out of practice. They have done few operations like this since the '90s."
ProPublica interviewed law enforcement, intelligence and diplomatic officials and experts from the United States, Europe, Israel and India for this article, granting them anonymity because of the ongoing investigation in Bulgaria and because many are not authorized to speak to the news media. They included officials from governments that do not always agree with Jerusalem and Washington about the nature of the Iran-Hezbollah threat.
Starting in the 1980s, Hezbollah and Iran conducted an international campaign of bombings, hijackings, kidnappings and assassinations against Israeli, U.S., European, Saudi and Iranian dissident targets.
In Argentina, car bombs blew up the Israeli embassy in 1992 and the AMIA Jewish community center in 1994, killing a total of 115 people. Argentine prosecutors charged that the Quds Force and Hezbollah used a web of diplomats, front companies and logistics specialists in the Lebanese diaspora.
Iran had "plots on the shelf methodically prepared and updated all over the world," said Charles (Sam) Faddis, a retired CIA counterterror chief. "They would do recon to test the defenses, update contingencies and plans."
In 2001, Deputy Secretary of State Richard Armitage called Hezbollah, which relies on Iran for funding, arms and support, "the A-team of terrorists." But the alliance scaled back international terror activity outside of combat zones such as Lebanon, Iraq and Afghanistan. Al Qaeda and its Sunni Muslim allies were the most urgent terror threat to the West during the past decade, but have declined dramatically in strength. Al Qaeda has not carried out a fatal bombing in the West since 2005.
In February, Iran allegedly tried to unleash a terror spectacular in the style of old, targeting three countries at once. A motorcycle bomber managed to wound an Israeli diplomat in India. But authorities foiled attacks in Georgia and Thailand 2014 where a bomber blew off his own legs 2014 even though a Quds Force commander had traveled undercover to Bangkok to lay the groundwork, according to Western counterterror officials.
Last year, Quds Force officers allegedly directed an Iranian-American used-car salesman to hire drug traffickers to assassinate the Saudi ambassador in Washington. But the suspect unknowingly recruited a U.S. Drug Enforcement Administration informant and was arrested; defense lawyers assert that their client has a mental disorder.
"It's as if there's a systematic policy of Iran recruiting low-rent, downright kooky terrorists," said British security expert Sajjan Gohel of the Asia-Pacific Foundation.
Another factor has played a role: In the aftermath of the 9/11 attacks, global defenses against terrorism have been beefed up. Still, Iranian spymasters have deployed seemingly inexperienced or ineffective agents, especially those with Western passports. The profile helps preserve deniability, according to Ali Alfoneh, an expert on the Iranian military at the American Enterprise Institute.