President Donald Trump and top defense officials are reportedly weighing whether to send ground troops to Iran in order to retrieve the country’s highly enriched uranium. However, the administration has shared little information about which troops would be deployed, how they would retrieve the nuclear material, or where the material would go next.

“People are going to have to go and get it,” secretary of state Marco Rubio said at a congressional briefing earlier this month, referring to the possible operation.

There are some indications that an operation is close on the horizon. On Tuesday, The Wall Street Journal reported that the Pentagon has imminent plans to deploy 3,000 brigade combat troops to the Middle East. (At the time of writing, the order has not been made.) The troops would come from the Army’s 82nd Airborne Division, which specializes in “joint forcible entry operations.” On Wednesday, Iran’s government rejected Trump’s 15-point plan to end the war, and White House press secretary Karoline Leavitt said that the president “is prepared to unleash hell” in Iran if a peace deal is not reached—a plan some lawmakers have reportedly expressed concern about.

Drawing from publicly available intelligence and their own experience, two experts outlined the likely contours of a ground operation targeting nuclear sites. They tell WIRED that any version of a ground operation would be incredibly complicated and pose a huge risk to the lives of American troops.

“I personally think a ground operation using special forces supported by a larger force is extremely, extremely risky and ultimately infeasible,” Spencer Faragasso, a senior research fellow at the Institute for Science and International Security, tells WIRED.

Nuclear Ambitions

Any version of the operation would likely take several weeks and involve simultaneous actions at multiple target locations that aren’t in close proximity to each other, the experts say. Jonathan Hackett, a former operations specialist for the Marines and the Defense Intelligence Agency, tells WIRED that as many as 10 locations could be targeted: the Isfahan, Arak, and Darkhovin research reactors; the Natanz, Fordow, and Parchin enrichment facilities; the Saghand, Chine, and Yazd mines; and the Bushehr power plant.

According to the International Atomic Energy Agency, Isfahan likely has the majority of the country’s 60 percent highly enriched uranium, which may be able to support a self-sustaining nuclear chain reaction, though weapon-grade material generally consists of 90 percent enriched uranium. Hackett says that the other two enrichment facilities may also have 60 percent highly enriched uranium, and that the power plant and all three research reactors may have 20 percent enriched uranium. Faragasso emphasizes that any such supplies deserve careful attention.

Hackett says that eight of the 10 sites—with the exception of Isfahan, which is likely intact underground, and “Pickaxe Mountain,” a relatively new enrichment facility near Natanz—were mostly or partially buried after last June’s air raids. Just before the war, Faragasso says, Iran backfilled the tunnel entrances to the Isfahan facility with dirt.

The riskiest version of a ground operation would involve American troops physically retrieving nuclear material. Hackett says that this material would be stored in the form of uranium hexafluoride gas inside “large cement vats.” Faragasso adds that it’s unclear how many of these vats may have been broken or damaged. At damaged sites, troops would have to bring excavators and heavy equipment capable of moving immense amounts of dirt to retrieve them.

A comparatively less risky version of the operation would still necessitate ground troops, according to Hackett. However, it would primarily use air strikes to entomb nuclear material inside of their facilities. Ensuring that nuclear material is inaccessible in the short to medium term, Faragasso says, would entail destroying the entrances to underground facilities and ideally collapsing the facilities’ underground roofs.

Softening the Area

Hackett tells WIRED that based on his experience and all publicly available information, Trump’s negotiations with Iran are “probably a ruse” that buys time to move troops into place.

Hackett says that an operation would most likely begin with aerial bombardments in the areas surrounding the target sites. These bombers, he says, would likely be from the 82nd Airborne Division or the 11th or 31st Marine Expeditionary Units (MEU). The 11th MEU, a “rapid-response” force, and the 31st MEU, the only Marine unit continuously deployed abroad in strategic areas, have reportedly both been deployed to the Middle East.