TEHRAN — Iran’s president on Sunday accused an unnamed US-allied country in the Persian Gulf of being behind a terror attack on a military parade that killed 25 people and wounded 60, further raising regional tensions.
Hassan Rouhani’s comments came as Iran’s Foreign Ministry summoned Western diplomats over their allegedly providing havens for the Arab separatists who claimed Saturday’s attacks in Ahvaz.
The Iranian moves, as well as promises of revenge by Iran’s Revolutionary Guard, come as the country faces turmoil following the US withdraw from Tehran’s nuclear deal with world powers. The attack in Ahvaz has further shaken the country.
Rouhani’s remarks could refer to Saudi Arabia, the United Arab Emirates, or Bahrain — close US military allies that view Iran as a regional menace over its support for militant groups.
‘‘All of those small mercenary countries that we see in this region are backed by America. It is Americans who instigate them and provide them with necessary means to commit these crimes,’’ Rouhani said before leaving for the UN General Assembly in New York.
Iran meanwhile summoned diplomats from Britain, Denmark, and the Netherlands early Sunday for allegedly harboring ‘‘members of the terrorist group’’ that launched the attack. Danish Foreign Minister Anders Samuelsen condemned the attack and stressed there would be ‘‘consequences’’ if it turns out that those responsible have connections to Denmark.
The ministry later summoned the UAE’s envoy, as well, over what it called the ‘‘irresponsible and insulting statements’’ of an Emirati adviser, according to the semi-official ISNA news agency. The UAE did not immediately acknowledge the summons.
Saturday’s attack, in which militants disguised as soldiers opened fire on an annual Iranian military parade in Ahvaz, was the deadliest attack in the country in nearly a decade. Women and children scattered along with Revolutionary Guard soldiers who had been marching as heavy gunfire rang out, the chaos captured live on state television.
Arab separatists, once only known for nighttime attacks on unguarded oil pipelines, claimed responsibility for the assault, and Iranian officials appeared to believe the claim. The separatists accuse Iran’s Persian-dominated government of discriminating against its ethnic Arab minority. Khuzestan province also has seen recent protests over Iran’s nationwide drought, as well as economic protests.
The attack killed at least 25 people and wounded 60, according to the state-run IRNA news agency. It said gunmen wore military uniforms and targeted a riser where military and police commanders were sitting. State TV hours later reported that all four gunmen had been killed.
At least eight of the dead served in the Revolutionary Guard, an elite paramilitary unit that answers only to Iran’s supreme leader, according to the semi-official Tasnim news agency. The guard responded to the attack on Sunday, warning it would seek ‘‘deadly and unforgiving revenge in the near future.’’
Tensions have been on the rise in Iran since the Trump administration pulled out of the 2015 nuclear accord in May and began restoring sanctions that were eased under the deal. It also has steadily ramped up pressure on Iran to try to get it to stop what Washington calls its ‘‘malign activities’’ in the region.
The US government nevertheless strongly condemned Saturday’s attack and expressed its sympathy, saying it ‘‘condemns all acts of terrorism and the loss of any innocent lives.’’
The Islamic State group also claimed responsibility for the attack in a message on its Amaaq news agency, but provided no evidence. They also initially wrongly said the Ahvaz attack targeted Rouhani, who was in Tehran. The militants have made a string of false claims following major defeats in Iraq and Syria.
On Sunday, IS militants posted a video online of three men, two of whom who spoke in Arabic extolling the benefits of martyrdom. A third who spoke in Farsi said they wanted to attack the guard. The video included no time stamps, nor any specific references to the Ahvaz attack.
The attack dominated Iranian newspaper front pages. The hard-line daily Kayhan warned that Iranians would demand Saudi Arabia feel the ‘‘hard slap’’ of the country’s power.
Iran’s government declared Monday as a nationwide public mourning day.
An overnight impromptu candlelight vigil in Ahvaz honored the dead and wounded. Among the dead is 4-year-old Mohammad Taha, who was captured by a photographer being carried away from the attack by a guardsman in full dress uniform and sash. The photo, showing the boy bloodied and helpless, shocked Iran.