On Thursday, 59 Tomahawk missiles were launched on the order of US President Donald Trump, evidently in response to the latest reports that Syrian dictator Bashar al-Assad had deployed deadly chemical weapons against a civilian population, killing dozens of people including children in Idlib province.

The US strike reportedly resulted in minimal casualties, and although it damaged the surrounding structures it left the airstrip itself operational, so that Assad was able to use it soon afterward to launch further strikes on rebel targets, something that US Senator Lindsey Graham described as a “serious mistake” and a brazen act of defiance against the Trump administration, according to CNN.

Last week’s strike was the first carried out by the US against a Syrian government target, although it has carried out a number of drone strikes against ISIL and other terrorist targets while providing logistical support to moderate rebels fighting to overthrow the Assad regime. Despite the recent strike’s minimal effects, the Iranian-Russian statement declared that the US had crossed “red lines.” It also threatened a non-specific response to the US or any other party that attacks Assad’s forces in the days ahead.

The statement was presumably prompted not only by the strike but also by accompanying statements from US officials, including Secretary of State Rex Tillerson. The remarks from the country’s leading foreign policy figure were seemingly non-committal regarding what sort of further action the Trump administration might take, but it spoke explicitly about Russian and Iranian “moral responsibility” while urging those Syrian allies to “have no illusions about [Assad’s] intentions.”

The Daily Beast accused Tillerson of dealing in euphemisms and avoiding the definitive conclusion expressed by one anonymous State Department official: that the available evidence clearly points to a war crime that was committed by Assad’s forces and either ignored or specifically enabled by Iran and Russia. Speaking days after Tillerson, US Ambassador to the UN Nikki Haley was less delicate, indicating that nothing was off the table in the wake of the Syrian allies’ rebuke, and adding that the US was “calling out” Iran and Russia over their support of the Assad regime.

CNN’s reporting upon Haley’s remarks also described competing narratives over what happened in Idlib province, where Assad and his allies have of course avoided taking responsibility for the chemical attack. Haley was unequivocal about the US having evidence of Assad’s guilt, and she also expressed severe criticism of Russian and Iranian efforts to cover up the facts. Tillerson, by contrast, declared his intention to bring up a 2013 agreement regarding the removal of Assad’s chemical stockpiles, when the Secretary of State next visited Moscow. He criticized Russia for failing to live up to its obligations under that deal, in light of the fact that the Assad government seems to have either retained supplies of sarin gas or synthesized more of it. But Tillerson added of Russia, “I don’t draw conclusions of complicity at all, but clearly they’ve been incompetent and perhaps they’ve just simply been out-maneuvered by the Syrians.”

Of course, no Trump administration officials have expressed similar skepticism about Iranian knowledge of the incident or Assad’s broader intentions. This is in keeping with the increasingly tense relations between the US and Iran following Trump’s successful presidential campaign during which he harshly criticized the Iran nuclear deal and the associated Obama-era foreign policy that virtually all Republicans and some Democrats considered to be much too conciliatory to the Islamic Republic and other traditional adversaries of the US.

By some accounts, Trump’s initial efforts to turn up the heat on Iran have paid dividends even though the Islamic Republic’s hardline anti-Western rhetoric remains undiminished. Although the Islamic Revolutionary Guard Corps’ boats continue to make provocative gestures toward US Navy vessels in the Persian Gulf and dual nationals continue to be the target of politically motivated arrests inside Iran, it is also reportedly true that some planned Iranian missile launches were scrapped after the White House put Iran “on notice” over a January ballistic missile test.

If it is true that Iran is scaling back some of its behaviors out of its concerns over an assertive US policy, this may be on display in what IranWire described as a “milder than expected” official response to the Idlib incident and the subsequent US missile strike. Although hardline Iranian media apparently followed its Russian counterpart’s lead in declaring that the deaths in Idlib were the result of damage to a rebel-held warehouse of chemical agents, the Iranian Foreign Ministry has so far declined to make this the government’s official position.

However, IranWire also notes that through unofficial channels a number of influential Iranian officials have issued even stronger denials of Syrian and Iranian responsibility for the civilian deaths. For instance, Alaeddin Boroujerdi, the head of the National Security and Foreign Policy Commission of the Iranian parliament, insisted that “terrorists have shown no hesitation in using chemical weapons” and that “the Syrian government has no chemical weapons,” even though similar chemical attacks in 2013 were internationally confirmed to have been the work of Assad’s forces.

Going even further, Ayatollah Mohammad Emami Kashani, a member of the Assembly of Experts which is tasked with the selection of a new supreme leader following his death or retirement, accused the US itself of deliberately supplying rebel groups with chemical weapons, apparently in the interest of carrying out a false flag operation to turn the international will against the Assad regime.

But such drastic measures seem remarkably unnecessary considering that various players in the international community seem to regard the US missile strike as having been long overdue. The Idlib attack prompted British Prime Minister Theresa May to quickly call for regime change in Syria, according to the Daily Beast. It is difficult to imagine that this represents an instantaneous policy shift on the part of the United Kingdom government, as opposed to a new elaboration on established preferences. In fact, although Ambassador Haley teased the possibility of regime change, Tillerson and other White House officials have remained cagey about this subject, suggesting that they are not pushing the rest of the world in that direction so much as they themselves are being pulled.

Indeed, according to the Daily Mail, European concerns over Assad’s potential retention of power are so strong that the newfound American pivot toward direct confrontation has been described as the start of “renewed harmony” between the US and its traditional allies. This was the phrase used by Italian Foreign Minister Angelino Alfano at the meeting of the G-7 nations in the city of Lucca.

The Daily Mail also noted that UK Foreign Secretary Boris Johnson is set to lead the effort to impose expanded sanctions on Russia unless it agrees to a solution to the Syrian crisis that involves Assad’s removal. Various analysts have suggested that Russia could be swayed in the direction of such a solution, although they have tended to conclude that the same is not true of Iran, which sees its interests being safeguarded only by the complete military defeat of Assad’s enemies.

Even though IranWire regards the official Iranian response as relatively mild, this conclusion about Iran’s interests in Syria seems to be supported by the fact that even President Hassan Rouhani, who has spearheaded outreach to the international community, took a hard line against the US in the wake of the missile strike.

“Americans have never acted within international frameworks, and one instance is the sanctions they impose against Iran, unreasonably considering themselves as the world’s leader. The Syrian people and army must give a response that makes Americans regret their attack,” he said according to the Daily Mail.

Rouhani’s commentary serves to underscore the tensions that exist between the Iranian regime’s foreign policy and his administration’s economic policy, which involves expanded international trade and the courtship of Western investment. Even as Rouhani and other officials lashed out against the US and its closest allies, the Iranian Oil Ministry continued to insist that it was anticipating excellent prospects for trade with and investment from Western entities.

UPI quoted Oil Minister Bijan Zanganeh as saying that foreign companies could be expected to invest to the fullest extent of the law. But as has been widely reported in recent months, many Western institutions are holding back their plans to re-engage with Iran until it is clear what further action the US might take as President Trump pursues a more assertive foreign policy. The newfound US involvement in Syria adds still further complexity to the situation, as does the fact that European powers are personally interested in sanctioning Russia over Assad’s criminal behaviors and thus might also show interest in broadening this sanctions effort to include the Islamic Republic.

As CNN notes, US Senate Majority Leader Mitch McConnell has already indicated that the legislative body is exploring the imposition of new sanctions against both Russia and Iran over their responsibility for the Idlib chemical attack. It remains to be seen whether these efforts will meet with the support of the US president or other Western heads of state. But it is already clear that the chemical attack and subsequent US response have helped to draw clearer lines between Assad’s allies and his adversaries.