Two teams of attackers used gunfire and explosives to strike Iran's parliament and the mausoleum of Ayatollah Ruhollah Khomeini in Tehran on Wednesday, according to state media. The twin attacks wounded at least 42 people and killed 12.
"Deputy Interior Minister Hossein Zolfaqari said that the terrorists had entered the parliament in [women's] dress," Iran's state news agency reports. It adds that a female assailant detonated herself outside the mausoleum.
The Iranian Intelligence Ministry says it foiled a third attack and is asking people to avoid public transportation, state broadcaster IRIB reports.
Islamic State, via its Amaq News Agency, claimed responsibility for the attacks, NPR's Alison Meuse reports.
Alison translated the extremist group's message to: "Fighters from the Islamic State have attacked the Khomeini shrine and the parliament building in central Tehran."
The report quotes an ISIS "security source," which Alison says is typical for such claims.
In an unusual move, the group also released a short video that it said was taken by one of the attackers inside the parliament. In it, a gunman is seen leaving an office area where a man lies wounded and not moving on the floor. A security siren and gunfire are heard as men yell in Arabic.
At the parliament building, four attackers reached the interior, where they shot at security guards. IRIB said that one of the attackers exploded a suicide vest inside the building, though other local news agencies said the explosion may have been caused by grenades thrown by the attackers.
The second attack — at the shrine of Khomeini, the nation's first supreme leader — came within an hour of the assault on the legislature. Assailants reportedly killed a security guard and wounded 12 other people, and a suicide bomber also detonated an explosive vest. Four attackers were said to have targeted the shrine.
Despite the violence at Iran's parliament Wednesday morning, lawmakers returned to business by the afternoon. Officials say the Islamic Revolutionary Guard Corps helped security forces control the situation.
"As you know, some coward terrorists infiltrated a building in Majlis [Parliament], but they were seriously confronted," Speaker Ali Larijani said. "This is a minor issue but reveals that the terrorists pursue troublemaking."
Iran is deeply involved in the fight against ISIS, both in Iraq and Syria and, together with Russia, is a major backer of the regime of Syrian President Bashar Assad.