Iran's semi-official news agency Fars News Agency tweeted a purported video of missiles firing and said "Start of Iran's vengeful US retaliation / Moment of Iranian missile firing at US base in Ain al-Assad."
News agency ANI tweeted a video of the same.
Iranian Revolutionary Guards have asked also US to 'recall US troops' from region, news agency AFP reported.
'Two ballistic missiles hit Erbil, No damage,' sources say
Of the two bases under attack, Erbil has suffered no damage as the missile did not explode after hitting the base, reports said.
One missile landed inside the perimeter of Erbil International Airport without exploding, the second missile hit an area 33 kilometers (about 20 miles) west of the city of Erbil without causing casualties.
US working on damage assessment
Pentagon spokesperson Jonathan Hoffman , said that the US is working on initial battle damage assessments.
Hoffman said around 5:30 pm on January 7, "Iran launched more than a dozen ballistic missiles against US.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 US military and coalition personnel at Al-Assad and Erbil, he said.
Earlier on Friday, the United States on Friday carried out a fatal strike against Soleimani in Baghdad. Iran has vowed to take the "harshest revenge" against Washington. Meanwhile, US President Donald Trump has threatened that his country will hit 52 Iranian sites if Tehran dares to take any action against the "preemptive" strike.
Trump monitoring situation closely:
President Trump has been briefed and is monitoring the situation, officials of the Pentagon were quoted as saying by the agencies.
White House Press Secretary Stephanie Grisham said that president has been briefed about the situation.
We are aware of the reports of attacks on US facilities in Iraq. The President has been briefed and is monitoring the situation closely and consulting with his national security team, Grisham said.
Hoffman said in recent days and in response to Iranian threats and actions, the Department of Defense has taken all appropriate measures to safeguard its personnel and partners.
These bases have been on high alert due to indications that the Iranian regime planned to attack our forces and interests in the region, he said.
Hoffman said "as we evaluate the situation and our response, we will take all necessary measures to protect and defend US personnel, partners, and allies in the region, Hoffman said.
(with inputs from agencies)