White House press secretary Jay Carney on Monday dismissed criticism from lawmakers over the administration's Taliban prisoner swap for Sgt. Bowe Bergdahl, saying the deal "should not have come as a surprise to members of Congress" because the basic outlines had been discussed for years.

"We had been working to secure Sergeant Bergdahl's release for a long time," Carney said at his daily briefing.

 This undated image provided by the U.S. Army shows Sgt. Bowe Bergdahl. (U.S. Army via AP)

The administration's failure to abide by legal requirements to inform Congress 30 days prior to releasing five Taliban prisoners over the weekend in exchange for Bergdahl, the last known prisoner of war in Afghanistan, has drawn rebukes from Republicans.

The White House has said that the president reserved the right to forgo the notice in extreme circumstances, and that the unique circumstances of Bergdahl's declining health and a narrow window for a deal convinced Obama that he had to move quickly or risk losing the deal.

Carney declined to specify Bergdahl's health problems, but a Pentagon spokesman told reporters that the serviceman, who had been in captivity more than five years, is receiving treatment for dietary issues at a U.S. military facility in Germany.

"Sergeant Bergdahl is in stable condition and is receiving treatment for conditions that require hospitalization," said Col. Steve Warren, a Pentagon spokesman, according to American Forces Press Service. "Part of that treatment process includes attention to dietary and nutritional needs."

Around noon Monday, the White House sent formal notification of the transfers of five Taliban prisoners from the military prison at Guantanamo Bay. One GOP congressional aide, speaking on condition of anonymity because the document is classified, said that congressional critics of the move are far from satisfied.

“It did not mitigate the concerns we have about recidivism, nor did it satisfy the requirement of the 2014 Defense Authorization Act” that such notice be given 30 days in advance.

Rep. Duncan Hunter (R-Calif.), a Marine Corps reservist who served in Iraq and Afghanistan, said in a letter to Obama that he remains "concerned by the sudden urgency behind the prisoner swap given other lines of effort offered the same opportunity for success. These efforts should have been fully exhausted before any commitment to exchange prisoners was made. Now a situation has been created whereby prisoner exchanges — specifically disproportionate exchanges — are viewed by the Taliban and other aligned forces as achievable."

But Carney emphasized that the United States is at war with the remnants of the Taliban government that was overthrown by U.S.-backed forces in 2001, and he called the prisoner exchange a standard wartime practice that did not equate to negotiating with terrorists, as some Republicans have charged.

The administration had opened discussions in 2011 with the Taliban over a possible prisoner exchange as a potential part of a negotiated end to the war, but the talks broke down in 2012. The administration said the Taliban re-engaged with U.S. officials in recent months, with the government of Qatar acting as an intermediary. As part of the deal, the five Taliban prisoners who were freed will live in Qatar under a year-long travel ban, officials said.

At a forum at the Center for Strategic and International Studies on Monday, White House Chief of Staff Denis McDonough also defended the move, saying: "We've been consulting with members of Congress about this effort, including the potential transfer of five Gitmo detainees, for years."