Since June, the U.S. military has been slowly stockpiling massive amounts of its gear coming out of Afghanistan at a depot in Kuwait adjacent to a bustling commercial port, in preparation for ultimately shipping it across the border into Iraq for an allied offensive against the Islamic State group.

The facility's warehouses and large asphalt yards now are home to roughly 3,100 vehicles, most of them MRAPs – the mine-resistant, ambush-protected vehicles that have been ubiquitous in America’s prolonged wars in Iraq and Afghanistan. There is also some electronic equipment and other supplies at the depot, located at Kuwait's Shuaiba port, defense officials say.

The gear, primarily from the Army, will be fixed up and held as top U.S. planners in Iraq determine what they’ll need to defeat the Islamic State group in the coming months, says Air Force Maj. Gen. Rowayne “Wayne” Schatz, the director of operations and plans for U.S. Transportation Command.

“From June to December, we’ve worked a lot on moving items into Kuwait,” he says. “The Army is holding the gear there, and it has room to hold it, as the mission fleshes out.”

The U.S. military and its allies are reportedly planning for a massive spring offensive to help Iraqi and Kurdish peshmerga fighters retake territory from the Islamic State group, particularly traditional Sunni Muslim bastions such as Anbar province west of Baghdad and the key city of Mosul.

Since 2012, the Defense Department has been destroying, selling or shipping out its gear in Afghanistan as the military neared its current number of 9,800 troops left behind to help the fledgling Afghan forces in 2015. The subsequent rise of the Islamic State group – also known as ISIS, ISIL or by the Arabic acronym “Daesh” – has forced the military to reroute some of that equipment back toward Iraq.

It represents a full circle for the protracted Middle East wars the U.S. continues to be drawn into: Much of the equipment taken out of Iraq during America’s complete withdrawal in 2011 was sent to nearby Afghanistan, where it had to be retrofitted to be effective in the rural mountains of the Hindu Kush and deserts of Helmand and Kandahar provinces, as opposed to the urban environments of Baghdad and Mosul. Now, as the war winds down in Afghanistan, the Islamic State group's sweeping incursion toward Baghdad has forced the U.S. to again focus its attention there.

U.S. Central Command ultimately will make the decision on how much of the equipment in Kuwait will be shipped into the newly ravaged war zone. The rest will be disposed of or sent back to the U.S.

The command did not respond to multiple requests for comment.

When asked about the strategy to defeat the Islamic State group on Thursday, the top U.S. general overseeing the campaign declined to offer specifics.

“I don’t want to disclose any timelines,” Lt. Gen. James Terry, commander of the Combined Joint Task Force-Operation Inherent Resolve, said during a news conference at the Pentagon. The task force is focusing on supporting, rebuilding and training Iraq's fractured military and National Guard forces to prepare them to take on the vicious extremist army.

Terry cited Mosul and Anbar province, along with the cities of Ramadi and Baiji, as key areas his forces will try to wrest away from Islamic State group control.

While the military stands by President Barack Obama’s repeated pledge that he will not put U.S. combat forces on the ground, an increasing number of U.S. troops has slowly trickled back into Iraq.

On Friday, the Pentagon announced Defense Secretary Chuck Hagel had ordered 1,000 paratroopers from the 82nd Airborne Division to join other advisers and trainers at headquarters in Baghdad and Irbil, as well as facilities elsewhere in the country. Roughly 1,700 troops are in Iraq already, with as many as 1,300 more to deploy.

The U.S. originally had planned to destroy, sell or give away as much as $7 billion worth of equipment it had in Afghanistan supporting the war effort there.

Since 2006, it has turned more than 1.1 billion pounds worth of equipment into scrap materials, according to documents provided to U.S. News by the Defense Logistics Agency. The steady destruction of gear viewed as useless or too expensive to move peaked in 2013, when the agency oversaw the destruction of 422 million pounds of equipment.

Some of the scrap is sold to Afghans to recoup costs. The Office of the Special Inspector General for Afghan Reconstruction, a congressionally created watchdog, has raised concerns about what it believes at times has been wasteful destruction of military equipment.

The military also conducts de facto yard sales to sell to Afghans some of its excess “white goods,” like power tools, air conditioning units, tractors, construction machinery, or mobile shower and bath units.

Those sales have brought in $2 million so far.

As of this summer, there was roughly $36 billion worth of equipment slated to return to the U.S. after being extricated from Afghanistan either by air and to nearby transfer facilities like the one in Kuwait, through a complicated land route north of Afghanistan, or through border crossings into Pakistan and on to one of that country's ports.

The latter two options have become less and less viable, says Schatz, whose command is tasked with moving military equipment and troops around the globe.

The U.S. drone campaign in Pakistan contributed to widespread political protests, prompting top leaders to occasionally close the main border crossing between Afghanistan and Pakistan at Torkham.

“We frankly found out at the start of the year we had major issues,” Schatz says. Delayed convoys coming out of Afghanistan also made for juicy targets for the Taliban, which has been conducting a surge in attacks as the U.S. withdraws its forces. “We had a backup early in the year of roughly 1,600 trucks waiting to get out.”

The land route to the north, known as the Northern Distribution Network, also is limited by some countries’ restrictions on combat equipment, such as armored vehicles, traveling over their land.

Transportation Command decided, as a result, to fly equipment from its main Afghanistan bases at Kandahar and Bagram to hubs in nearby countries like Oman, the United Arab Emirates and Kuwait for processing and ultimate shipment back to the U.S.