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Gunmen linked to the Islamic State launched a brazen assault in Tehran on Wednesday, attacking the country's parliament building and the shrine dedicated to revolutionary Iran's founder, Ayatollah Ruhollah Khomeini. At least 17 people were killed and dozens more wounded.

It was the first time in more than a decade that Tehran was struck by militants. Thomas Erdbrink, the New York Times's correspondent in Tehran, reported the details: "The attacks started around 10:30 a.m., when men armed with assault rifles and suicide vests — some of them dressed as women — descended on the Parliament building, killing at least one guard and wounding and kidnapping other people. That standoff lasted until midafternoon."

Iranian policemen evacuate a child from the parliament building in Tehran on June 7. (Omid Vahabzadeh/Agence France-Presse via Getty Images)

Five assailants were killed. The Islamic State claimed responsibility through its online channels and released a graphic 24-minute video showing a bloody scene from Iran's parliament.

The implications of the attack "are huge," Charlie Winter, a senior research fellow at the International Center for the Study of Radicalization at King’s College in London, told my colleagues. For Sunni extremists, "attacking Iran is kind of like attacking the U.S. or Israel."

Iran sits at the vanguard of Shiite Islam. It is an ideological nemesis of jihadist groups such as the Islamic State and features prominently as a target in the propaganda of some Sunni fundamentalists. Iranian proxy militias in Iraq and Syria, to varying extents, have been locked in battles with the Islamic State and other extremist outfits.

In the wake of the assault on Tehran, condemnations and condolences poured in from around the world. The European Union's top foreign envoy, Federica Mogherini, expressed her sympathies for the victims and said it is "obviously a very sad day again for us anytime there is a terror attack anywhere in the world." French President Emmanuel Macron called his Iranian counterpart, Hassan Rouhani, and apparently discussed expanding "cooperation in the fight against terrorism," according to an Iranian official. Russian President Vladimir Putin condemned "these crimes" and pledged Russia's "readiness for further joint actions" with Iran.

And then there was President Trump.

The White House has made a particular habit of commenting swiftly on Islamic State-related attacks elsewhere, be they in Paris, London, Manchester or even a phantom episode in the Philippines. But for many hours Wednesday, Trump was conspicuously quiet. The State Department's spokeswoman issued a pro forma condemnation, asserting that "the depravity of terrorism has no place in a peaceful, civilized world."

When Trump ultimately broke his silence, though, his message snuffed out whatever goodwill American diplomats may have wanted to convey.

"We grieve and pray for the innocent victims of the terrorist attacks in Iran, and for the Iranian people, who are going through such challenging times," began the statement, before concluding with a startling swipe at Tehran. "We underscore that states that sponsor terrorism risk falling victim to the evil they promote."

It's tacky and heartless in any context to try to score political points when lamenting the loss of innocent lives. But even given the pronounced tensions between Tehran and Washington — made all the more acute by the Trump administration putting Iran "on notice" — Trump's statement seemed to cross an unspoken line in world affairs. Iranian officials, after all, issue their own routine condemnations of terrorist attacks in the United States, such as last year's massacre at a nightclub in Orlando, without suggesting that the Great Satan was getting its comeuppance. After the attacks of Sept. 11, 2001, Iranians held candlelight vigils.

As we've written in this space before, the Trump administration's hostility to Iran is part of its wholesale embrace of the agenda and rhetoric of Iran's major rivals in the region — Saudi Arabia and Israel. The leaders of both those countries see Iran as an existential threat, a destabilizing actor that backs dangerous groups across the region. There is plenty of truth in this view, given the extent to which Iran's powerful and hard-line Revolutionary Guard Corps dominates the country's foreign policy and supports militancy elsewhere.

But Iran was not attacked by Hezbollah, the influential Lebanese Shiite organization it backs. It was hit by a terrorist group whose ideology is far closer to the creed preached by Saudi clerics than the theologians of Qom, a phenomenon conveniently ignored by the White House and its partners. To be sure, previous administrations have for decades acquiesced or turned a blind eye to the destabilizing effect that Saudi-backed fundamentalism has had on the Muslim world. Yet a Trump administration that is overtly opposed to "radical Islam" has chosen to embolden the Saudis like never before.

Just hours after the attack, the U.S. Senate voted overwhelmingly to push forward a bill that would impose new sanctions on Iran. A few Democratic senators urged a postponement of the proceedings, given the timing. But they were overruled.

Meanwhile, Iran's Revolutionary Guard pointed the finger at Washington and Riyadh, the usual suspects in its eyes. "The public opinion of the world, especially Iran, recognizes this terrorist attack — which took place a week after a joint meeting of the U.S. president and the head of one of the region’s backward governments, which constantly supports fundamentalist terrorists — as very significant," it said in a statement, referring to Saudi Arabia.

Given the already intensifying standoff between feuding Arab monarchies in the Persian Gulf, it seems the region's many fault lines are only deepening in the early months of the Trump presidency.

The National Iranian American Council, a Washington-based organization that seeks rapprochement between Iran and the United States, issued an angry response to the White House statement.

"We underscore that administrations that cannot empathize with human suffering risk losing their humanity," it read, "and presidents who cannot genuinely recognize victims of terrorism are incapable of leading the fight against terror."

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