The Pentagon said Wednesday it had turned to a private charity to fund death benefits for families of US soldiers killed on duty after the government shutdown forced a suspension of the payments.

The announcement came hours after President Barack Obama demanded urgent action and as the plight of four families who lost loved ones in Afghanistan grabbed headlines, sparking public outrage.

Defense Secretary Chuck Hagel said Fisher House Foundation, a private charity devoted to helping combat veterans, had agreed to finance the death benefits while the Pentagon would reimburse the group once government funding was restored.

But Hagel expressed disgust that political deadlock in Congress had forced the extraordinary step.

"I am offended, outraged, and embarrassed that the government shutdown had prevented the Department of Defense from fulfilling this most sacred responsibility in a timely manner," Hagel said in a statement.

"In the days before the shutdown, we warned Congress and the American people that DoD (Department of Defense) would not have the legal authority to make these payments during a lapse in appropriations," he said.

Obama's spokesman, Jay Carney, said earlier the US president had called on officials to resolve the problem and that he was "disturbed" about the halt in funding.

"The president was very disturbed to learn of this problem and he directed the Department of Defense to work with the Office of Management and Budget and his lawyers to develop a possible solution," Carney said.

"The president expects this to be fixed today."

Carney repeatedly declined to say exactly when Obama found out about the issue.

He also accused Republicans of causing the problem by shutting down federal operations by not passing a new budget before October 1, and for not including the provision in a bill already signed by Obama to ensure soldiers on deployment still get paid during the shutdown.

Republican lawmakers in turn blamed Obama and his fellow Democrats for the shutdown and for the suspension of death benefit payments.

Relatives of soldiers killed on the battlefield abroad or on duty at home are normally entitled to $100,000 in death benefits, housing allowances and financing for burial costs.

Since October 1, when the partial shutdown began, 17 troops have been killed and none of their families have received the $100,000 payment.

Earlier Wednesday, Hagel travelled to Dover Air Force Base in Delaware to pay his respects to four soldiers killed this week in Afghanistan, officials said.

Hagel met with families of the four US Army soldiers at the Dover base, which processes the remains of all fallen troops.

The four soldiers, identified as First Lieutenant Jennifer Moreno, 25, Sergeant Patrick Hawkins, 25, Sergeant Joseph Peters, 24, and Private Cody Patterson, 24, were part of a joint special operations task force. They died on Sunday in the Zhari district in an explosion from a homemade bomb, according to the Pentagon.