The US military's efforts in the Middle East are aimed to ensure the free flow of energy from the region and prevent weapons of mass destruction, a Pentagon official said.

Derek Chollet, the assistant secretary of defense for international security affairs, said Thursday that in the region, the Pentagon will continue to thwart al-Qaida and its associated movements and confront external aggression directed at US allies.

The Pentagon is keenly focused on building the capacity of our partners to fight extremism and support US national security interests, Chollet said.

"We're working hard to sustain and enhance our military capabilities in the region," he said.

"As US military forces have withdrawn from Iraq and Afghanistan, we are also addressing questions from regional partners about our intentions ... and commitments over the long term," Chollet said.

Currently, he said, US and allied forces have a military presence of more than 35,000 personnel in and around the Arabian Gulf. And in line with the Pentagon's recent release of the Quadrennial Defense Review, the commitment will not wane, he said.

So far, Chollet reported, the Iraqis have purchased from the United States about 250 million US dollars in key capabilities, such as Hellfire missiles, ground tanks, rockets, small arms and ammunition.

"Those articles have either been delivered or expected to arrive in the next weeks," he said.

DOD has also provided equipment and training to supplement the Jordanian border security program and improve the capability of its military to detect and interdict illegal crossing and attempts to smuggle weapons of mass destruction, Chollet added.