Why ISIS Just Attacked Its 'Mortal Enemy' Iran for the First Time

This article originally appeared on VICE News.

The Islamic State claimed responsibility for deadly gun and bomb attacks in the heart of Iran's capital Wednesday that killed at least 12 and injured 42 more. The attacks represent the group's first strike on Iranian soil, providing a significant morale boost for the Islamists and further inflaming tensions between regional powerhouses Iran and Saudi Arabia.

Simultaneous attacks were launched on two hugely symbolic targets: the Iranian parliament building in central Tehran and the mausoleum of the Islamic Republic's founder, Ayatollah Ruhollah Khomeini, an Iranian official told state broadcaster IRIB. A third attack was foiled, Iran's Intelligence Ministry said.

Shia-majority Iran is one of the most influential forces in the fight against the Sunni terror group, which regards Shia Muslims as apostates.

"(Iran is) a mortal enemy of the Islamic State, not just for the differences in theology, but because of the fighting in Iraq and Syria," said Bill Roggio, editor of the Long War Journal.

The attacks began Wednesday morning when four gunmen stormed Parliament and opened fire. A suicide bomb was detonated during the attack, which lasted about four hours before the attackers were killed, Iran's semi-official Fars news agency reported. The attack on the mausoleum began shortly afterwards and also involved a suicide bomb, according to reports.

ISIS immediately claimed responsibility for the assaults, as it has for a number of terror attacks around the world throughout the Islamic holy month of Ramadan.

There have reportedly been previous unsuccessful attempts by ISIS to strike Iran. Last June, Iranian security forces said they had thwarted a major bombing plot targeting Tehran and other major cities during Ramadan.

Tehran is a key backer of Syrian President Bashar al-Assad, providing, along with Russia, critical military support to his beleaguered regime. But Roggio says Iran had been even more effective against ISIS in neighboring Iraq, where it has emerged as a key ally of the Shia-dominated government, and has "established, armed, trained, and funded numerous militias that are now officially institutionalized as a legitimate security force, called the Popular Mobilization Forces."

Sanam Vakil, a Middle East expert at the Johns Hopkins School of Advanced International Studies, says ISIS had in recent months called for attacks on Iran. Recent propaganda efforts have included Farsi-speaking jihadists calling on the country's Sunni minority to strike.

Terror attacks have been rare in Iran, especially in the capital, compared to many other countries in the region and in Europe — a source of pride for Iranian officials, Vakil said, adding that the government's success in guaranteeing security was a key plank in the recent reelection of President Hassan Rouhani.

Vakil said the strike would only embolden Iran in its activities against ISIS in Syria and Iraq, "because now they have an imperative to protect their security."

The attack will also undoubtedly raise tensions even higher in the region, coming days after Iran's Sunni arch-rival Saudi Arabia moved to isolate Qatar, the sole Gulf nation that maintains relations with Iran. The major diplomatic rift comes just weeks after U.S. President Donald Trump pledged to isolate Iran during a meeting in Riyadh.

The timing didn't go unnoticed by Iran's military. The powerful Islamic Revolutionary Guard Corps released a statement shortly after Wednesday's attack implicating both Saudi Arabia and the U.S.

"This terrorist attack happened only a week after the meeting between the U.S. president and the backward leaders who support terrorists," the statement read, according to Reuters. "The fact that Islamic State has claimed responsibility proves that they were involved in the brutal attack."

Hours before Wednesday's attacks, Saudi Foreign Minister Adel al-Jubeir characterized Iran as the leading sponsor of terrorism and called for action to be taken against it over its destabilizing actions in the region, where it is involved in Lebanon and Yemen, as well as Syria and Iraq. In turn, Iran blamed Saudi Arabia for supporting the rise of Sunni extremist groups in the region.

Trita Parsi, author of Losing an Enemy: Obama, Iran and the Triumph of Diplomacy says Iranian officials had long been worried that Saudi Arabia would instigate a confrontation with Iran or strike on its territory. Blaming Saudi Arabia, Parsi says, may be an effort to shift international anger toward the Saudis, rather than an indication that Iran planned to take action in response.

But if Iran did take action, he said, "then obviously we're looking at a very negative scenario."