Iran’s caretaker Prime Minister Adel Abdul Mahdi on Tuesday condemned the rocket attack on the US embassy in the Iraqi capital, calling it “unacceptable”.

Mahdi’s office as stating after the weekly cabinet meeting that “Yesterday, Katyusha rockets were fired at the US embassy, and this is painful and incorrect … Who authorises those parties to attack the embassy in Iraq?”.

“This act offends Iraq and is unacceptable regardless of their intentions,” Abdul Mahdi said without naming the attackers.

The attack at the Baghdad International Airport also killed Abu Mahdi al-Muhandis, the deputy commander of Iran-backed militias known as the Popular Mobilisation Forces (PMF).

Iran’s Supreme Leader Ayatollah Ali Khamenei swiftly pledged to take “severe revenge” for Soleimani’s assassination.

On Wednesday, Iran fired more than a dozen missiles at two Iraqi bases that house US forces. US and Iraqi officials said there were no casualties.

No group has so far claimed responsibility for the attack which came after growing tensions between the US and Iran.

The Iranian attack came after a US drone attacked on January 3 a convoy at Baghdad International Airport, killing Qassem Soleimani, commander of the Quds Force of Iran’s Islamic Revolution Guards Corps, and Abu Mahdi al-Muhandis, deputy chief of Iraq’s paramilitary Hashd Shaabi forces.

More than 5,000 US troops have been deployed in Iraq to support the Iraqi forces in the battles against Islamic State militants.

(With inputs from agency)