Iran's Islamic Revolutionary Guard Corps (IRGC) said Wednesday that it targeted Ain al-Asad airbase in Iraq, a facility jointly operated by U.S. and Iraqi forces, with "tens of missiles".

"In Operation Martyr Soleimani in the early hours of Wednesday, tens of ground-to-ground missiles were fired at the U.S. base and successfully pounded Ain al-Asad Base," the IRGC said in an official statement.

It said the shelling “is merely the beginning of a series of revenge attacks with no deadline for when it ends," it said.

"We warn all allied countries of the U.S. that if attacks are launched from bases in their countries on Iran, they will be a target of military retaliation," it added.

A second wave of missile attacks against American forces in Iraq has begun, Iran’s Tasnim News Agency announced.

The Islamic Revolutionary Guard Corps warned on their Telegram channel that in the event that Iranian soil is bombed, they would launch a third wave of attacks to destroy Dubai and Haifa.

Meanwhile, Iranian military sources claimed that at least 30 U.S. soldiers in Iraq had been wounded in the attacks.

Tasnim also reported that Hezbollah has threatened to strike Israel if the U.S. retaliates against Iran, while Iraq's Hashd al-Shaabi group, or Popular Mobilization Units (PMU), said they have launched their own retaliation attacks against U.S. bases.

Iran's Fars news agency called the firing of the missiles at Ain al-Asad airbase a "hard revenge" in a Twitter post. 

The Pentagon confirmed that the attacks occurred at approximately 5:30 p.m. (EST) on Tuesday, with Iran launching more than a dozen ballistic missiles against U.S. military and coalition forces in Iraq.

"It is clear that these missiles were launched from Iran and targeted at least two Iraqi military bases hosting U.S. military and coalition personnel at Al-Asad and Irbil," said Pentagon spokesman Jonathan Hoffman in a statement. 

The Pentagon is working on initial battle damage assessments.

The U.S. military confirmed that six missiles had made an impact.

White House Press Secretary Stephanie Grisham said: "We are aware of the reports of attacks on U.S. facilities in Iraq. The president has been briefed and is monitoring the situation closely and consulting with his national security team."

Qassem Soleimani, the head of Iran's Revolutionary Guards Corps' elite Quds Force, was killed in a U.S. drone strike outside Baghdad airport early Friday. 

His death marked a dramatic escalation in tensions between the U.S. and Iran, which have often been at a fever pitch since President Donald Trump chose in 2018 to unilaterally withdraw Washington from a 2015 nuclear pact world powers struck with Tehran. 

Iranian Supreme Leader Ali Khamenei, who bestowed the country's highest honor on Soleimani last year, vowed "severe retaliation" in response to his killing.