The family of US soldier Bowe Bergdahl have received death threats after his release from five years of Taliban captivity, according to US authorities.
Bergdahl has faced criticism amid claims he abandoned his post in Afghanistan before being captured, having asked his commanding officer if he would be punished for walking off his base.
The soldier's hometown of Hailey, Idaho, where the 28-year-old's parents Bob and Jani live, has been swamped with hate mail and angry telephone calls.
It would have been offensive and incomprehensible to consciously leave an American behind.
William Facer, a spokesman for the FBI, said on Saturday that the agency continued to monitor the situation and took each threat seriously.
On Wednesday, Hailey, which has a population of 8,000, cancelled plans for a welcome-home parade, citing security concerns over the prospect of big crowds - both for and against the soldier.
Bergdahl's freedom was secured last week by a swap deal for five high-profile Taliban members, who were released from the prison in Guantanamo Bay.
He was filmed several times by his Taliban captors, in some instances making statements about his opposition to the war.
Some Republican politicians have questioned whether the swap deal was lopsided in favour of the Taliban.
John Kerry, the US secretary of state, said on Sunday there was time to sort through exactly what happened in Afghanistan but he fiercely defended the exchange.
"It would have been offensive and incomprehensible to consciously leave an American behind. No matter what," he said.
He added that the five Taliban members, who are restricted to living in Qatar for a year, faced death if they took up arms against the US.
"These guys pick a fight with us, in the future or now or at any time, at enormous risk," he said.
The US army is currently deciding if disciplinary action is needed against Bergdahl.