The top military official involved in the raid that killed Osama bin Laden said Tuesday that the Obama administration has no clear plan for handling suspected terrorist leaders if they are caught alive outside a war zone.

Vice Adm. William H. McRaven told a Senate panel that contingency plans for detaining terrorism suspects are developed on an ad hoc basis and approved by the White House, but that there are no set rules. “That is always a difficult issue for us,” he testified. “No two cases seem to be alike.”

In response to senators’ questions, McRaven said that “in many cases” suspects captured in secret operations by Navy SEALs or the Army’s Delta Force are taken to a U.S. Navy ship until they can be tried in a U.S. court or transferred to the custody of an allied country. But if neither option turns out to be feasible, the prisoner is ultimately let go, he said.

“If we can’t do either one of those, then we will release that individual,” McRaven said in response to a question from Sen. Lindsey O. Graham (R-S.C.). “I mean, that becomes the unenviable option, but it is an option.”

McRaven did not describe any specific cases in which prisoners were freed.

He and Lt. Gen. John R. Allen, Obama’s nominee to become commander of U.S. and NATO forces in Afghanistan, said the military had recommended against transferring any terrorism suspects captured in countries such as Somalia, Yemen or Pakistan to U.S. detention centers in Afghanistan because of political resistance there.

“It’s not our intention” to move prisoners to Afghanistan, Allen said.

McRaven elaborated, adding: “We have looked a number of times at whether or not we would do that in Afghanistan, but owing to the nature of the sovereignty of Afghanistan and the concern about the potential backlash from the Afghan government, we have recommended not to do that.”

Their statements marked a shift from previous testimony by administration officials. In February, CIA Director Leon Panetta said that if al-Qaeda’s top leaders were captured, they would first be taken to a U.S. military detention center near Bagram air base in Afghanistan.

“We would probably move them quickly into military jurisdiction at Bagram and then eventually move them probably to Guantanamo,” Panetta told the Senate Intelligence Committee. He has since been named defense secretary and begins that job Friday.

McRaven, however, seemed to rule out taking captured terrorism suspects directly to the U.S. naval base at Guantanamo Bay, Cuba.

Asked by Sen. Kelly Ayotte (R-N.H.) whether Guantanamo Bay is “still off the table” as a place to detain and interrogate terrorism suspects for long periods, McRaven replied: “As far as I understand it, it is, yes, ma’am.”

The Obama administration has said it is committed to closing the prison at Guantanamo Bay. The base still houses 170 detainees captured in the aftermath of the Sept. 11, 2001, attacks.

The last time a prisoner was moved to Guantanamo Bay was in March 2008, during the George W. Bush administration.

McRaven currently leads the Joint Special Operations Command, which deployed the team of Navy SEALs that tracked down and killed bin Laden in May at a compound in Abbottabad, Pakistan. The mission was overseen by Panetta and the CIA.

The administration has said that it was prepared to capture bin Laden alive if he had surrendered, but it has not spelled out what plans it might have had for his detention.