The Pentagon is considering allowing the families of detainees at Guantanamo Bay to visit them, an unprecedented step to ease the isolation of inmates who in some cases have been held at the U.S. facility for close to a decade, according to congressional aides.

The International Committee of the Red Cross (ICRC), which monitors conditions at the military prison in Cuba and facilitates videoconferences between detainees and their families, has been in serious discussions with the Pentagon about a visitation program, the aides said.

Some Republicans, after hearing about the talks, appeared to balk at such access to the Guantanamo Bay naval station. In an early version of the annual legislation to authorize the activities of the Defense Department, Rep. Howard P. “Buck” McKeon (Calif.), the chairman of the House Armed Services Committee, inserted language that would ban family visits, which have never occurred at the prison.

But the latest version of the bill states only that Defense Department funding appropriated for fiscal 2012 may not be used “to permit any person who is a family member of an individual detained at Guantanamo to visit the individual.”

That would not rule out a visitation program underwritten by the Red Cross.

“My efforts are aimed at protecting U.S. personnel at Guantanamo and sensitive national security information from being compromised,” McKeon said Wednesday. “Allowing family members to visit detainees at Guantanamo Bay would create major security concerns for our nation.”

A spokesman for the ICRC, Simon Schorno, said the organization would not comment on its confidential dialogue with the U.S. government. But he said that “regardless of where detainees are held, particularly in the context of long-term detention, the ICRC will always work for the detainees and their families to be in contact with one another, including through family visits.”

The Pentagon also would not discuss any potential visitation program or its talks with the ICRC. In response to questions, the department said in a statement that “we are constantly reviewing detention policies with regard to our detention operations globally.”

Congressional aides familiar with the talks spoke on the condition of anonymity because of the sensitive nature of the discussions.

Because Guantanamo is off-shore, families would not necessarily need to enter the mainland United States to reach the prison, and the visits could be staged from a neighboring country willing to allow the families to move into and out of the base.

The “high-value detainees” held at the top-security Camp 7 — including Khalid Sheik Mohammed, the self-proclaimed mastermind of the Sept. 11, 2001, attacks — would almost certainly not be allowed to participate in any family-visit program. They are currently forbidden to communicate by phone or teleconference, although they can send letters to relatives.

The prospect of family visits is another tacit acknowledgment that Guantanamo is unlikely to close anytime in the near future, and it follows the creation of a review process for those detainees whom the Obama administration said it plans to hold indefinitely without trial.

There are 172 detainees remaining at Guantanamo, 48 of whom are expected to be held indefinitely under the laws of war. Most of the detainees live communally in barracks or open prison-style wings.

Family visits to detainees in U.S. custody are not without precedent, and the ICRC advocates around the world for the principle of visitation.

The United States allows face-to-face contact at a visitation facility at Bagram air base, the largest U.S. detention center in Afghanistan, and both the George W. Bush and Obama administrations, working with the Red Cross, have expanded the ability of detainees at Guantanamo to communicate with their families.

Inmates at the facility were first allowed to send letters home via the Red Cross in 2002, shortly after the detention center opened. The contents of letters are reviewed and in some cases censored by the military. The ICRC says it has facilitated the exchange of more than 50,000 messages between Guantanamo detainees and their families.

Starting in 2008, detainees who met certain conditions set by the military were allowed one phone call home each year. That was later expanded to allow several calls each year. More than 700 telephone calls have been made since the system was set up, according to the ICRC.

The military has refused to describe what conditions detainees must meet to be permitted to make phone calls, or whether the calls are a reward for what it calls “compliant” behavior.

In October 2009, the military began to allow one-hour videoconference calls between detainees and their immediate families or other close relatives. Video-call locations have been set up in 20 countries, according to the ICRC.

All conversations are monitored by the military, and the participants are cautioned to limit their topics to family news and other matters that don’t raise security concerns.

The ICRC is the only independent organization that monitors conditions at Guantanamo and has access to the detainees, including the high-value inmates. The ability of people outside the U.S. government to visit the prison is strictly limited.

Defense lawyers can meet their clients at Guantanamo, and journalists and human rights activists can attend legal proceedings. Some relatives of victims of the Sept. 11 attacks have also attended military commission proceedings at the base.