Terrorists attacked two key sites in Tehran on June 7 — the Parliament building, a symbol of the republic, and the tomb of the Islamic Republic’s revolutionary founder, Ayatollah Ruhollah Khomeini, a symbol of the revolution. Sixteen people died and 45 were wounded. The group that calls itself the Islamic State (ISIS) took responsibility and promised to inflict more harm on Iran.

This coordinated attack was unprecedented since the Mojahedin-e-Khalq, an Islamist Marxist cultish militant group, bombed a gathering of the upper echelons of the regime in 1981, which killed scores, including then President Mohammad Ali Rajai, Prime Minister Mohammad Javad Bahonar and Mohammed Beheshti, second in command to Ayatollah Khomeini. Since then, Iran has gained extensive counterterrorism experience fighting an array of domestic and foreign groups. In fact, observers credited this sophisticated apparatus for shielding Iran from the type of high-profile attacks ISIS has inflicted in European countries.

The twin attacks in Tehran are a major blow to President Hassan Rouhani, who promised to boost security during his recent re-election campaign. As is well known, Rouhani and his moderate coalition want to normalize the regime’s relations with the world and reintegrate Iran into the community of nations. To this end, the Rouhani government signed the Joint Compressive Plan of Action (JCPOA), referred to by its Persian acronym as Barjam.

Rouhani and the normalizers strongly criticized the hardline Islamic Revolutionary Guard Corps (IRGC) for continuing Iran’s intervention in wars in Syria, Iraq and Yemen. Gholam Hossein Karbaschi, the former reformist mayor of Tehran and a Rouhani supporter, stated: “We too want peace … for the oppressed to be defended and the Shi’ites to be supported. But this cannot be done by giving money, buying arms and killing.”

While few have gone so far as to call Syria the “Iranian Vietnam,” the view that the war there is costly and, ultimately, unwinnable, has affected public opinion. Polls indicate that support for the regime’s involvement in Syria had fallen from a peak of 90 percent in recent years to a low of 24 percent.

In the aftermath of the terrorist attacks, this may change. Hardliners were quick to blame the Rouhani government. They sarcastically slammed Rouhani for saying that he had removed the shadow of war from Iran through the nuclear deal. Kayhan newspaper, a mouthpiece of Supreme Leader Ayatollah Ali Khamenei, attributed the assault on Rouhani’s victory in the elections and concluded that the attack reflected the poor performance of the government. The daily wrote, “When you [Rouhani] slammed and weakened the Revolutionary Guards for testing missiles, when you questioned all of the past 38 years, it gave a good opportunity to America, Israel, and Saudi Arabia to fill the gap with security challenges.”

Hamid Rasaei, a parliamentary member representing former president Mohammed Ahmadinejad’s hardline camp known as the Principalists, stated, “Terrorists are here to help coward statesmen.” Others went further, calling Rouhani a traitor and sarcastically questioned him by saying “Wasn’t it you that just said there would be war if I am not elected?” Principalists also attacked Karbaschi and others who have criticized the IRGC’s commitment to Syrian President Bashar al-Assad. Ahmad Tavakoli, a conservative politician and journalist, wrote on his Instagram: “When I heard about the ISIS attack…. I told myself ‘congratulations’ to Mr. Karbaschi and his like-minded ones.”

There is little doubt that the hardliners will use the ISIS onslaught to try to derail Rouhani’s normalization project, most notably his call to end Iran’s interventionist foreign policy. The old argument that involvement in the Syrian civil war is an investment in the security of Iran has moved front and center in the public discourse. Added to the likely rally-around-the-flag effect of the terrorist attacks, they strengthen the view that engagement in Syria, Iraq and further afield would keep the country “an island of stability” in the regional “sea of chaos.” As if on cue, a video began circulating on social media bearing the caption, “if we don’t fight ISIS in Syria, you would fight it in Iran.” The recording showed an interrogation of an ISIS jihadist captured in Iraq who promised to “cut off the heads” of Iranians because they are even “dirtier than the Jews.”

It is also possible that the situation would lead to a further securitization of Iran domestically. The Ministry of Intelligence and Security is overseeing the investigation, but other security forces such as the Intelligence division of the IRGC will probably step up its activities in the guise of looking for subversives. So far, the authorities have refrained from imposing emergency regulations but have asked citizens not to congregate in large groups unless necessary.

Further restrictions on social and political freedoms of Iranian citizens cannot be ruled out. Ethnic and religious minorities, especially the Sunni minority, would be most vulnerable in the new security climate.

Farhad Rezaei is a research fellow at Center for Iranian Studies (IRAM) in Ankara where he researches Iran’s foreign policy. He is the author of Iran’s Nuclear Program: A Study in Proliferation and Rollback  (New York: Palgrave Macmillan, 2016). His writings have appeared in Harvard-Iran Matters,   the National Interest, Middle East Policy, British Journal of Middle Eastern Studies, Journal of International Affairs,   Insight Turkey and  Asian Affairs among others. His new book is  Iran’s Foreign Policy after the Nuclear Agreement: The Politics of Normalizers and Traditionalists, Palgrave Macmillan, forthcoming. He tweets at @Farhadrezaeii