This morning, 25 people were murdered by gunmen in Southwestern Iran after a military parade in Ahvaz, the capital of Khuzestan, a province housing most of the country’s Arab minority, was attacked. The parade, one of Iran’s many nationwide Sacred Defense Week celebrations, meant to commemorate Iran’s eight-year war with Iraq, saw not only the 25 casualties, but another 60 people severely wounded by the attacks. The victims include a mix of Islamic Republic Revolutionary Guards Corps soldiers and civilians watching the parade.  

Four gunmen disguised in military uniforms—two of whom were killed and two of whom were captured—were responsible for the atrocious attack. Until recently, the identity of the gunmen and the agents behind the attack, however, remained unknown. Some officials accused Arab separatists. The local television held Islamic State fighters accountable. The Islamic State and separatist group Al Ahwaz, however, just released statements claiming responsibility for the killings.

Iranian foreign minister Mohammad Javad Zarif tweeted this morning holding “terrorists recruited, trained, armed & paid by a foreign regime” responsible for the attacks. A great deal of anti-U.S. sentiment was contained in the minister’s statement as well. “Iran holds regional terror sponsors and their U.S. masters accountable,” he charged on Twitter.

An Iranian general informed the Islamic Republic News Agency that the four gunmen were trained by two Persian Gulf countries.

Iran, a predominantly Shia Muslim country, has faced many attacks by militant branches of the Sunni minority. This Saturday’s, however, marks one of the deadliest.

The Shia government is usually quick to blame the U.S., Israel, and neighboring Sunni states in response to these attacks.

Ahvaz, the city in which this morning’s attack occurred, is no stranger to this kind of anti-government sentiment. The city is an oil production hub, yet receives very little revenue or reinvestment from the oil sales themselves, sparking a great deal of this resentment.

The meeting of the UN General Assembly, slated to occur next week, will be critical in terms of defining international response to today’s events. Iran’s foreign minister has already blamed the U.S. for the attacks. A spokesman for the Iranian military has further claimed the gunmen’s actions were linked to Israel and the United States, according to a recent BBC report, indicting both America and its ally.

Regardless of whoever is behind the gunmen’s attack, it is critical that the practice of killing innocent civilians as an act of political protest come to an end. Murder is no way to address the religious tension between the Shia and Sunni in Iran; it not only costs civilian lives, but also invites more violent, inflammatory acts.