The US military said on Tuesday that it knocked down an Iranian missile barrage and worked with Saudi Arabia's forces to strike sites in Iraq that Tehran-backed militias have used to launch attacks in recent days, shattering a brief pause in fighting.

Iraq's Popular Mobilisation Forces (PMF) said that the attacks killed 20 people. The PMF, an alliance of of former paramilitary groups and factions now integrated into the Iraqi armed forces, said another 32 fighters were wounded in the surprise US attacks on its bases across seven provinces, according to a preliminary toll.

Earlier, the US Central Command said in a statement that it had intercepted Iranian missiles launched against American forces in the Middle East, adding that they “remain vigilant and at a high state of readiness.”

In announcing the strikes in Iraq, the US warned that further attacks on American troops or Saudi Arabia’s energy infrastructure risked additional action.

Iran launched its ballistic missile attack before US and Saudi forces carried out strikes in Iraq, according to an American official, who stressed that the two attacks were not connected.