In an event that could significantly escalate security concerns and sectarian tensions in a region beset with civil war and spreading terrorist violence, several gunmen and a suicide bomber carried out two separate attacks in Iran on Wednesday, killing at least 12 and injuring dozens more.

One attack took place inside the Iranian Parliament building, and the other at the site of the shrine of Ayatollah Ruhollah Khomeini, the Islamic Republic’s founder. ISIS has claimed responsibility through its news agency.

CNN reported:

The violence unfolded at about 10 a.m. local time (2 a.m. ET) when gunmen apparently dressed as women stormed the main gate of the parliament building in central Tehran and opened fire.

The attackers took a number of hostages and at least one detonated a suicide bomb. Sporadic gunfire was heard before Iranian authorities declared the situation under control about four hours later. All four attackers were killed by security forces, the semi-official Fars news agency reported.

The attack comes at a time of simmering hostility between regional powers resulting from, among other factors, the Syrian civil war and President Donald Trump’s numerous public statements declaring his intent to isolate and weaken Iran. Trump has also frequently expressed strong support for Iran’s fiercest rival, the kingdom of Saudi Arabia, which he recently visited on his first foreign trip as president.

“In the view of many in Iran,” the New York Times noted, “the Islamic State, also known as ISIS or ISIL, is inextricably linked to Saudi Arabia.”

While European representatives were quick to condemn the atrocities, President Trump has thus far remained silent, as has Saudi Arabia—facts several commentators highlighted Wednesday morning.