The U.S. Southern Command said Wednesday it has requested additional guards for the prison camps at Guantánamo, with the goal of reaching a 2,000-strong staff at the detention center of 166 captives.

Part of the reason is the ongoing hunger strike that has most prisoners under lockdown. As of Wednesday, the Pentagon had 1,831 troops and civilians assigned to the prison, including 15 extra public-affairs troops training 20 replacements.

“When you go to single cell, that takes more people,” said Navy Capt. Robert Durand, the prison spokesman, who reported Wednesday night that 124 reinforcements from the Texas-based 591st Military Police Co. arrive at Guantánamo on Saturday.

Another 125 troops from a Puerto Rico based 613th MP Co., an Army Reserves unit, was training at Fort Bliss, Texas, to relieve other guards currently based at Guantánamo as part of a regular rotation, he said.

But Navy Lt. Cmdr. Ron Flanders, a Southcom spokesman, said the Doral headquarters that oversees the prison camps had already planned to add more units of soldiers to the camps with the goal of reaching 2,000 personnel.

Part of the reason, he said, is anticipation that the Guantánamo war court, where six men are facing capital terror tribunals called military commissions, might be “ramping up.” And part of it was to add more replacements for individual sailors who had served in the prison staff.

In January, the last sailor guards at the communal Camp 6 departed and were replaced by Army MPs. Soon after that, the new Army guards carried out a communal cellblock search that the prisoners’ lawyers say sparked the hunger strike. As of Wednesday, the prison reported that 103 detainees were on hunger strike and 39 of them were being tube-fed by Navy medical staff, three in the prison hospital.

At Southcom, Flanders said the 125-member Puerto Rican MP force “would kind of come in handy right now because we’re in single-cell operations. They have the experience and the know-how in that unit.” The Puerto Rican MPs come from “civilian careers in law enforcement,” he said.

As of Wednesday, all but about 15 of the detainees were in “single-cell confinement,” each prisoner kept in a solitary cell at Guantánamo following an April raid that put the once showcase communal Camp 6 under lockdown.

In recent years, a majority of captives lived communally, more like traditional prisoners of war. They ate and watched TV in groups; were allowed to pray together, up to 40 at a time at one point; played soccer; and tended to their own daily needs on their own clocks.

Guards stepped back and the work was less labor-intensive.

But prison commanders said the communal captives disobeyed their guards, and, in one abuse of the privilege, covered up the surveillance cameras in their communal cellblocks. So in April, troops raided the prison and locked most of the prisoners into individual cells, requiring more work from the guards who deliver food through slots, and shackled up each man to leave his cell for most activities — from showers to outdoor recreation cells and indoor TV rooms where they are confined alone.

In April, Flanders said, Southcom sent down 37 medical reinforcements to help deal with the hunger strike — a doctor, nurses, and corpsmen.

That raised to about 140 the number of Navy medical staff specifically assigned to care for the prisoners.

Wednesday’s staff figure of 1,831 troops and civilians are specific prison staff who rotate out mostly annually from the remote base in southeast Cuba.

Elsewhere on the base, another 4,000 sailors, contractors, and family members are full-time residents.

The disclosure of additional troops came on the day the senior Democrat on the House Armed Services Committee estimated that taxpayers pay $1.6 million per detainee each year.

Rep. Adam Smith, D-Wash., said in a news release that the cost was in contrast to $34,046 for a maximum-security prisoner in the Federal Bureau of Corrections.

The estimate is a bit uneven because the federal corrections costs don’t include the price of running the federal courts while Smith’s estimate includes the maintenance of Guantánamo’s Camp Justice and Office of Military Commissions — the war court where six of the 166 detainees await trial. Only three other captives have been to the war court and the remainder do not face any charges there.

A spokesman for the HASC chairman, Rep. Buck McKeon, R-Calif., did not immediately respond to a request for his estimate of the per-prisoner cost at Guantánamo.

At the Pentagon, Army Lt. Col. Todd Breasseale said the Defense Department did not have a specific figure but said the detention center’s annual operating budget had been “relatively steady at approximately $150 million.”

“If you divide the total number of detainees into that number, that certainly provides a kind of estimate,” he said, “but I believe it to be an imprecise one.”

That figure crunches to about $900,000 a year. Breasseale noted that a higher estimate could be reached by “lumping the costs of all things associated” with the detainees, from the detention center to the military commissions’ cost. “But that appears to make an assumption that all detainees are eligible for prosecution when most are Law of War detainees.”

President Barack Obama in a policy speech at the National Defense University last month crunched the same operating costs this way: “During a time of budget cuts, we spend $150 million each year to imprison 166 people — almost $1 million per prisoner.”