The announcement came a day after the US military said the Abraham Lincoln carrier strike group had arrived in the Middle East, dramatically boosting American firepower in the region.

The exercise will "demonstrate the ability to deploy, disperse, and sustain combat airpower across" the Middle East, the US Air Force component of Central Command, which is responsible for American forces in the region, said in a statement.

No date or exact location for the exercise were released.

The protests in Iran started in late December, driven by economic grievances, but turned into a mass movement against the Islamic republic, with huge street demonstrations for several days from January 8.

A US-based rights group said Tuesday it had confirmed the deaths of over 6,000 people in protests, adding that it was investigating over 17,000 more potential deaths.

President Donald Trump had repeatedly warned Iran that if it killed protesters, the United States would intervene militarily, and also encouraged Iranians to take over state institutions, saying "help is on the way."

But he pulled back from ordering strikes earlier this month, saying Tehran had halted more than 800 executions under pressure from Washington.