Less than 24 hours after the House passed a resolution to limit the President’s ability to wage war on Iran, the U.S. launched airstrikes against Iran-backed militia groups across five locations in Iraq. The strikes were in retaliation for attacks that killed two Americans and one U.K. medic Wednesday, the Pentagon confirmed Thursday night.

“We’re going to take this one step at a time, but we have to hold the perpetrators accountable. You don’t get to shoot at our bases and kill and wound Americans and get away with it,” Esper said. We’ve been very clear about this.”

The strikes targeted facilities that “housed weapons used to target U.S. and coalition troops,” a Defense Department statement said.

“These strikes were defensive, proportional, and in direct response to the threat posed by Iranian-backed Shia militia groups who continue to attack bases hosting coalition forces,” the Pentagon statement said. “These terror groups must cease their attacks on U.S. and coalition forces or face consequences at a time and place of our choosing.”

The strikes appeared to target the Shia militia group Kata’ib Hezbollah, Gen. Frank McKenzie, commander of U.S. Central Command, intimated during Congressional testimony Thursday. The Shia militia group reportedly attacked another Iraqi military base in December, which led to President Donald Trump’s decision to kill Iranian Quds force Commander Gen. Qassem Soleimani.

The ongoing clashes between Iranian-backed militias and U.S. forces in the region caused some lawmakers to question whether the “maximum pressure” campaign against Iran instituted by President Trump and favored by Secretary of State Mike Pompeo has been successful. The Trump administration had touted Soleimani’s killing at the end of January, saying that it would deter future Iranian attacks.