Sniping between the White House and Republicans plumbed new depths of pettiness Wednesday, with no progress evident toward ending a standoff which closed the government and could spin the United States into default.

Nine days into a government shutdown and eight days before a deadline to raise the US debt ceiling, Washington was stalemated, with neither side ready to climb down from entrenched positions.

President Barack Obama sat down with House of Representatives Democrats and invited all other lawmakers to the White House to discuss the crisis in the next few days.

But Republicans, saying Obama's invitation was a waste of time if he would not negotiate, said only party leaders, and not the rank and file of their restive caucus would show up at the White House.

There was public outrage meanwhile over the plight of families deprived of death benefits for military members killed overseas since the shutdown started, before a charitable organization stepped up to fill the funding gap.

Washington is lurching ever closer to an October 17 deadline to raise the US government's statutory borrowing limit. Failure to do so could see the country default on its obligations for the first time in history.

The Organization for Economic Cooperation and Development (OECD) warned Wednesday that a default could throw most of the world's major economies "back into recession next year" and badly damage emerging nations.

The US government, has largely been shuttered for nine days, after Congress failed to agree on a budget to finance operations by an October 1 deadline.

Warning he would not be held to ransom, Obama has said he will refuse to negotiate with Republicans on long term budget issues until the debt limit is lifted and the government reopened.

Republican House Speaker John Boehner, however, will not take either step until Obama offers concessions to his House Republican caucus.

A spokesman for Boehner said that the talks at the White House would only be worthwhile if a solution was on the agenda.

"That's why the House Republican Conference will instead be represented by a smaller group of negotiators, including the elected leadership and certain committee chairmen," said Boehner spokesman Brendan Buck.

White House spokesman Jay Carney said Obama was "disappointed that Speaker Boehner is preventing his members from coming to the White House."

"The President thought it was important to talk directly with the members who forced this economic crisis on the country about how the shutdown and a failure to pay the country’s bills could devastate the economy."

While both sides are locked into their positions, and no in-depth negotiations are taking place, there were some signs of political maneuvering Wednesday that could indicate key players are looking for an endgame.

Republican Paul Ryan, a conservative chieftain in the House, weighed in on the debate with an op-ed article in the Wall Street Journal, rebuking Obama for not negotiating over the debt ceiling -- saying presidents had repeatedly done so in the past.

The Wisconsin congressman and 2012 vice presidential nominee called for a wide discussion about budgetary policy, and offered Democrats a conversation about reining in some spending in return for concessions on the funding of social programs.

While the article broke little new ground, it did not mention defunding Obamacare, the president's legacy-enhancing health care law which Republicans have been trying to cripple in return for opening the government or raising the debt ceiling.

Lawmakers were also Wednesday chewing over Obama's offer to accept a short-term extension to the debt ceiling and temporary government financing to forestall the immediate crisis, which has sparked alarm over possible economic impact globally.

Chris Van Hollen, a senior Democratic congressman, said there was a "little glimmer" of hope for a way out.

"It depends on whether Republicans on the Hill are willing to ... jump on it," Van Hollen said on CNBC.

It is unclear, however, whether Boehner has the votes within his own party to push forward a short-term solution.

The Republican speaker has been unwilling to rely on Democratic votes to build a majority in the House, apparently fearing a backlash from conservative Tea Party members who could put him out of a job.

Obama, meanwhile, demanded action after learning that relatives of service members killed in Afghanistan since the shutdown began had not received $100,000 in death benefits.

"The president expects this to be fixed today," White House spokesman Jay Carney said, though he refused to say when Obama found out about the issue.

The Pentagon said later that a private charity, the Fisher House Foundation had offered to fund the death benefits and would be paid back when the shutdown ends.

Defense Secretary Chuck 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.