The U.S. military is looking at a new way of holding detainees in the field, according to government procurement records: small, prefabricated cells, designed for solitary custody and barely big enough to lie down in, that could be deployed to war zones.

The Army is looking for information from contractors who could design and build a "modular detainee shelter system," according to an announcement on fbo.gov that was posted in November. Each "closed, box-like" shelter would be "a holding cell for one detainee during combat operations."

Two former military officials familiar with detention in combat zones said that at times, commanders have had to come up with detention options on the fly. In Afghanistan, for example, prisoners were kept in tents in Kandahar in the early days of the conflict, and then transferred to a warehouse on the Bagram air base. In Iraq, prisoners were sometimes held in large shipping containers or tents.

These new cells, which would be collapsed for transportation, would have "tamperproof" interiors. The door to the cell could be padlocked shut from the outside, and would have a five-inch square window, also tamperproof. The door would also have two small access holes, one for passing food to the inmate, and the other for locking and unlocking handcuffs.

The cells, as described in a detailed sheet, would have an internal area of at least 40 square feet, and would stand eight feet with a width of about seven feet. They would have heat and air-conditioning and be able to hold their detainees in any environment, from the South Pole to the Sahara. The "operational temperature" of the cells would be from 40 degrees below zero to 120 degrees, and would be designed to resist not just "the effects of blowing sand," but also a heavy load of snow, according to the specifications.

When the Army was done with the cells, they could be disassembled and shipped away.