(CNN) The US carried out airstrikes on Thursday against multiple Iranian-backed militia sites in Iraq, according to the US Defense Department.

The strikes come one day after the US assessed an Iranian-backed group was responsible for a rocket attack on a base where coalition forces are located, killing two American service members and one British service member.

The Defense Department on Friday identified the two US service members killed in the attack as Army Specialist Juan Miguel Mendez Covarrubias, 27, of Hanford, California and Air Force Staff Sgt. Marshal D. Roberts, 28, of Owasso, Oklahoma. The UK Ministry of Defense had earlier identified the slain UK service member as Lance Corporal Brodie Gillon.

The UK government expressed support for the US airstrikes, with the UK's Defense Secretary Ben Wallace saying "We support the right of the United States to defend themselves, as they have done tonight."

A US defense official told CNN that the strikes were carried out by manned fighter aircraft and targeted five weapons storage facilities.

In a written statement, the Defense Department stated the strike was aimed at harming the ability of Kata'ib Hezbollah, an Iranian-sponsored Shia militia group, to conduct future strikes against American troops. The weapons storage facilities included areas where weapons used to attack American and coalition troops were stored.

"These strikes were defensive, proportional, and in direct response to the threat posed by Iranian-backed Shia militia groups (SMG) who continue to attack bases hosting OIR coalition forces," the department statement read.

The statement added, "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 US and the coalition remain committed to the lasting defeat of ISIS, and the long-term security, stability, and sovereignty of Iraq."

Gen. Kenneth McKenzie, the commander of US Central Command which oversees US forces in the Middle East, told reporters Friday that the strikes had targeted storage sites housing "advanced conventional weapons" that he said had been provided to the militias by Iran, such as the 107mm rockets which were used in the deadly attack on Wednesday.

"We are confident that we have effectively destroyed these facilities and expect they will not longer be able to house the type of advanced Iranian-supplied weapons that were used in the Khatib Hezbollah attacks on the Iraqi base at Camp Taji," McKenzie said.

US Central Command also released images purporting to be the weapons storage facility targets hit in the airstrikes that took place near Baghdad.

The Iraqi government condemned the airstrikes in a statement Friday, saying that several Iraqi security force personnel were killed or wounded in the strikes.

Khatib Hezbollah, the Iranian-backed militia the US says was responsible for Wednesday's attack, is ostensibly part of the Iraqi security forces.

"These locations that we struck are clear locations of terrorist bases," McKenzie said Friday when asked about Iraq's opposition to the strike.

"If Iraqi military forces are there, I would say it's probably not a good idea to position yourself with Khatib Hezbollah in the wake of a strike that killed Americans and Coalition members," he added.

Tension with Iran

The strikes come months after the US and Iran were brought to the brink of war in early January. While the situation appeared to deescalate in the weeks following Iran's retaliatory strike on a base housing US troops in Iraq, tensions have flared up once again between Tehran and Washington.

There have been multiple rocket attacks in Iraq in recent weeks, but Wednesday's was the first to cause a US death since December, when a US contractor was killed. That death prompted retaliatory US airstrikes against Iranian-backed militia targets in Iraq and Syria. Trump administration officials pointed to the contractor's death as their justification for air strikes that killed Iran's second most powerful leader, Gen. Qassem Soleimani.

The US was reviewing options as to how to respond, the US Defense secretary and top US general said earlier on Thursday.

"Yesterday's attack by Iranian backed Shia militia groups consisted of multiple indirect fires that originated from a stationary platform and was clearly targeting coalition and partner forces on Camp Taji," Secretary of Defense Mark Esper told reporters at the Pentagon while pledging that the US would take action to hold the attackers accountable.

"We're going to take this one step at a time. But we've got 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.

President Donald Trump told reporters Thursday that he had been working on what to do about the attack on Wednesday night.

"They've sent a lot of rockets now. It hasn't been fully determined it was Iran," Trump said.

He added, "It was a rebel group, but most likely it looks like it could be backed by Iran."

Gen. Mark Milley, the chairman of the Joint Chiefs of Staff, said Thursday that the truck that fired the approximately 30 107mm rockets was captured by the Iraqi Security Forces and that forensics from that vehicle helped identify the attackers.

"We have pretty good confidence who did this. We were able to capture the truck, it was a modified truck with tubes, rocket tubes on the back, the Iraqi security forces did a good job in helping secure that truck. We have good indications based on forensics where it was fired from, who did the firing and so on and so forth," Milley said.

Milley said that 14 coalition personnel were also wounded in the attack, including five injuries that were considered "urgent." Those wounded included US, British, Polish and contractor personnel.

"The groups responsible will be held accountable appropriately," Milley said, adding, "it was a significant attack and it resulted in the death and wounding of American (service members). So where we go from here as you would expect options are on the table and we are looking at everything and we will await final options and decisions from the President."

Coronavirus effect

The series of strikes come as both Iran and the US struggle to deal with the coronavirus outbreak.

McKenzie said Thursday he thinks the coronavirus outbreak in Iran "is having an effect on how they make decisions," and that "their inability to effectively respond to the coronavirus is I think inducing pressure on and inside the leadership."

McKenzie said he thinks the coronavirus outbreak in Iran "is having an effect on how they make decisions," and that "their inability to effectively respond to the coronavirus is I think inducing pressure on and inside the leadership."

"I think it probably makes them, in terms of decision making, more dangerous rather than less dangerous. But that's just my assessment," said McKenzie, adding that he believes "the numbers are probably significantly underreported in terms of coronavirus victims in Iran."

Asked why the Iranian groups chose to attack now, Milley said, "There could be a lot of reasons, it could be coronavirus, it could be rogue Shia militia groups, it could be Soleimani's birthday, it could be a lot of things."

McKenzie on Thursday said the outbreak was also "going to have some effect on the military instrument" when asked about the Iranian regular military and IRGC at a Senate Armed Services hearing.

The coalition strikes come one day after the House of Representatives approved a War Powers resolution aiming to rein in presidential authority to use military action against Iran without congressional approval.

The resolution -- introduced by Sen. Tim Kaine, a Virginia Democrat -- passed the Senate last month with bipartisan support despite Trump's vocal opposition.

It will now be sent to the White House, where Trump is expected to veto it. Congress is not expected to have enough votes to override a presidential veto. Although it is unlikely to become law, passage of the resolution by both chambers represents a significant rebuke to the President and highlights congressional support for efforts to check the executive branch's war-making powers.

This story has been updated with additional developments.