Several opposition Republicans issued statements welcoming yesterday's release of Sergeant Bowe Bergdahl.
But several Republicans also claimed that his exchange for "terrorists" held in the Guantanamo Bay detention centre would just encourage more kidnappings of US soldiers.
Lawmakers were not told of the Guantanamo prisoner transfer until after the swap, the Washington Post reported.
Mike Rogers, chairman of the House intelligence committee, said that he is "pleased that Sergeant Bergdahl is free and will be returning to his family in the United States."
"This fundamental shift in US policy signals to terrorists around the world a greater incentive to take US hostages," Rogers said.
"I believe this decision will threaten the lives of American soldiers for years to come," he said.
Influential Republican Senator John McCain demanded to know what steps were being taken to "ensure that these vicious and violent Taliban extremists never return to fight against the United States and our partners."
He described the men being released as "hardened terrorists who have the blood of Americans and countless Afghans on their hands."
"America has maintained a prohibition on negotiating with terrorists for good reason," Representative Howard "Buck" McKeon and Senator James Inhofe said in a joint statement.
"In executing this transfer, the president also clearly violated laws which require him to notify Congress thirty days before any transfer of terrorists from Guantanamo Bay and to explain how the threat posed by such terrorists has been substantially mitigated."
The law was indeed not followed, a senior US official told the Post, speaking on condition of anonymity.
