Central Command commander General Kenneth McKenzie said the two carrier groups would be staying in the region for a sustained period in the wake of a series of attacks on US positions in Iraq by Iranian-backed groups that have ratcheted up tensions with Tehran.

Early Friday the US military launched air strikes against weapons depots of Kataeb Hezbollah, an Iraqi armed faction that receives support from Iran.

The strikes were in retaliation to Wednesday's rocket attack, attributed to Kataeb Hezbollah, that killed two American and one British soldiers at Iraq's Taji air base.

Showing journalists before and after surveillance photographs of the five sites, McKenzie said the US strikes effectively destroyed them, degrading the Iraqi group's ability to carry out attacks.

"We are confident that we have effectively destroyed these facilities and expect they will no longer be able to house the type of advanced Iranian supplied weapons that were used in the Kataeb Hezbollah attacks on the Iraq base at Camp Taji," he said.

He accused Tehran of continuing to support attacks against US and coalition forces via its proxies in Iraq.

To maintain an effective ability to counter such threats, the Pentagon had authorized keeping the two aircraft carriers in the Gulf for the first time since 2012.

With the two carriers in the region, he said, "We have the flexibility, the capability and the will to respond to any threat," McKenzie said.

"I think the threat remains very high. I think that tensions have actually not gone down," he added.

"I would caution Iran and its proxies from attempting a response that would endanger US and coalition forces," he said.