Baghdad/Washington, Jan 17 (IANS): Eleven US troops were injured in the January 8 Iranian missile attack on of the two American bases in Iraq, despite the Pentagon initially saying that no service member was hurt, it was reported on Friday.

"While no US service members were killed in the January 8 Iranian attack on Al Asad air base, several were treated for concussion symptoms from the blast and are still being assessed," Xinhua news agency reported citing Captain Bill Urban, spokesman for thr US Central Command, as saying.

On January 8, Iran had launched tens of surface-to-surface missiles on the two Iraqi military bases hosting US military and coalition personnel at Ayn al Asad and Erbil, which was in retaliation to the January 3 killing of Iranian Major General Qasem Soleimani in an American drone attack near the Baghdad airport.

Following the attack, the Pentagon had said that no casualty was reported.

Urban added that some service members received "follow-on screening" as a measure of caution and consequently the symptoms were found.

Eight persons were transported to Germany and three sent to Kuwait for further screening, Xinhua news agency quoted a CNN report as saying.

CNN also reported that an anonymous US defence official claimed that the symptoms of the injured troops emerged "days after the fact".

Currently, more than 5,000 US troops are deployed in Iraq to support the country's forces in the battle against the Islamic State terror group.

Shortly after the missile attack, President Donald Trump had tweeted that "all is well", adding "we have the most powerful and well equipped military anywhere in the world, by far".

Iran had vowed "severe revenge" over the death Soleimani, who was the chief of the Islamic Revolutionary Guard Corps' elite Quds Force.