One of the Patriot batteries was deployed to the Ain al-Asad base last week and was being assembled, according to a US defense official and an Iraqi military source, AFP reported.

The base was targeted by Iran in January, following a US strike that assassinated top Iranian General Qassem Soleimani.

The US is planning to send another two Patriot batteries to Iraq, although the systems are still in Kuwait awaiting deployment, a US official said.

Another battery was deployed to a base in Erbil, the capital of the autonomous Kurdistan Region in the north of Iraq.

The Patriot systems are composed of high-performance radars and interceptor missiles that can track and destroy incoming ballistic missiles while they are still in the air.

Washington and Baghdad have been negotiating the placement of the defense system for months, as tensions between the US and Iran show no signs of cooling off. But it was not immediately clear whether the US had ultimately received the Iraqi government's approval.

Most of the violence that has taken place between the US and Iran has taken place on Iraqi soil.

Iraqi parliament called for the US to withdraw all of its forces on January, a request the US government has largely ignored.

Top Iraqi officials who met US Central Command chief General Kenneth McKenzie in February suggested Washington could grant Baghdad some political "cover" by reducing its troop presence in Iraq as it deployed the missiles. And in recent weeks the US-led coalition has significantly drawn down troop levels in Iraq.

Reporter’s code: 50101