Hard-right House Republicans are “holding the entire US government hostage” as a shutdown appeared all but certain and could have a “significant effect” on the morale of active-duty US troops, the national security council (NSC) spokesman warned early on Friday. John Kirby, the NSC spokesman, noted that 1.3 million active duty military personnel will not get paid if the government shuts down, and added in an interview with ABC on Friday morning that hundreds of thousands of civilian Pentagon employees also will have to be furloughed. That would be just one effect among many others across federal government functions that will be affected as the Republican-controlled House of Representatives is deadlocked over proposed spending plans to keep the government open. “The first and most immediate impact is that those 1.3 million active-duty troops won’t get paid. They will still be out there … defending this country but they won’t get paid,” Kirby said on ABC’s Good Morning America. “Nobody joins the military to get rich. Every paycheck matters, and you miss a couple and it starts to show up in terms of your ability to pay your bills … it will have a significant effect on their morale. It won’t just be them, though, it will be the civilian employees of the defense department … they won’t be allowed to show up for work,” Kirby said. Kirby also warned that a shutdown could have implications for military aid to Ukraine as it continues its counteroffensive against the Russian invasion, as well as the government’s capacity to “restock our own shelves” with military supplies. He said the government was in the process of informing its workers, military and non-military across the country how a shutdown will work. Unless there is a significant and, at this stage, unexpected breakthrough in Washington on Friday or Saturday, the federal government will be forced to shutdown its spending channels at 12.01am on Sunday. The shutdown appeared all but inevitable late on Thursday as the House speaker, Republican Kevin McCarthy, was hemmed in by extremist representatives of his own party who appear to be gearing up to try to oust him as well as, at the urging of Donald Trump, stop the government in its tracks. McCarthy has vowed he will not take up Senate legislation designed to keep the federal government fully running into November, despite his struggle to unite fellow House Republicans around an alternative. “There’s not a lot we can do here at the White House,” Kirby said on Friday, continuing to tell ABC: “This is between Speaker McCarthy and a small group of House Republicans that want to hold the entire US government hostage. This is between him and his caucus and they need to solve this problem.” McCarthy, however, has not given up on finding a way through. The Senate is working toward passage of a bipartisan measure that would fund the government until 17 November as longer-term negotiations continue, while also providing $6bn for Ukraine and $6bn for US disaster relief. The House, meanwhile, has teed up votes on four of the dozen annual spending bills that fund various agencies in hopes that would cajole enough Republicans to support a House-crafted continuing resolution that temporarily funds the government and boosts security at the US border with Mexico. It’s a long shot, but McCarthy predicted a deal. “Put your money on me; we’re going to get this done,” he said in a CNBC interview. “I think we can work through the weekend. I think we can figure this out.” The House minority leader, the New York Democrat Hakeem Jeffries, told CNBC on Friday morning that his caucus would pass the Senate’s funding bill if it reached the lower chamber. But without a majority in the House or a bipartisan deal with McCarthy – which could be a death knell to his speakership as the hard-right phalanx would turn on him decisively – that bill is dead on arrival in the House. Meanwhile, as well as budget problems for the military and a host of government assistance programs such as food stamps and other nutrition benefits, entrances to national parks will be blocked and thousands of park rangers will be furloughed, the interior departement said on Friday. The stance is a reversal from five years ago when the Trump administration kept some parks open in a move that has been lambasted as illegal by the Government Accountability Office, the congressional watchdog. This time around, the majority of more than 420 national park units will be off-limits to the public, interior officials said. The governors of Arizona and Utah vowed to keep some of the most well-known parks open with state funding, including Grand Canyon and Zion. Places like the National Mall will stay open, but there are no guarantees that restrooms or trash will be maintained. “The public will be encouraged not to visit sites during the period of lapse in appropriations out of consideration for protection of natural and cultural resources, as well as visitor safety,” the interior department said in a statement.