By Jason Mannet

An unnamed donor is giving $130m (£100m) to the Pentagon to help pay US troops during the government shutdown, sparking ethics concerns.

US defence officials confirmed the gift, which President Donald Trump said will make up for shortfalls in paying the country's 1.32m service members, but declined to identify the donor.

Trump provided a few clues, though, saying on Saturday that he was "a big supporter of mine" and a US citizen.

The government shut down more than three weeks ago, after lawmakers failed to approve a funding deal. The Trump administration paid troops last week by shifting $8bn from military research, but it is unclear what will happen on the next payday at the end of the month.

Now in its 26th day, the shutdown is poised to become one of the longest in US history.

Treasury Secretary Scott Bessent said on Sunday the US would probably be able to pay the military "beginning in November".

"But by November 15 our troops and service members who are willing to risk their lives aren't going to be able to get paid," he told Face the Nation, a talk show on CBS, the BBC's US news partner. "What an embarrassment."

The next military payday is scheduled for 31 October, at the end of this week.

Pentagon spokesman Sean Parnell told reporters on Friday that the donation "was made on the condition that it be used to offset the cost of service members' salaries and benefits," and it was allowed under the department's "general gift acceptance authority".

Trump had indicated a donation would be made on Thursday, while also declining to identify the donor, saying "he doesn't really want the recognition".

However, the New York Times has identified the benefactor as Timothy Mellon, a billionaire and major financial backer of Trump.

Mr Mellon is the heir to his influential family's $15bn (£11bn) fortune, according to Forbes, and was heavily involved in the US railway industry before recently becoming more politically active and donating $50m to a group supporting Trump.

Before leaving for Asia on Saturday, Trump told reporters at the White House that the donor was a "great gentleman", a "patron", a "patriot" and a "wonderful man" who "doesn't want publicity".

"He prefers that his name not be mentioned, which is pretty unusual in the world I come from," Trump said. "In the world of politics, you want your name mentioned."

"He put up $130 million in order to make sure - that's a lot of money - in order to make sure that the military got paid, and he's a big supporter of mine," he continued.

The funds amount to around $100 per servicemember.

The White House was able to reallocate some military research funds to make the last military payday, while lawmakers in Congress have tried, and so far failed, to pass a bill that would keep troops being paid during the shutdown.

Most government workers have been furloughed, or in some cases, told to work without pay while the shutdown lasts.

According to Defence Department rules, donations over $10,000 must be reviewed by ethics officials "to determine whether the donor is involved in any claims, procurement actions, litigation, or other particular matters involving the Department that must be considered prior to gift acceptance".

Donations from non-American citizens require additional scrutiny.

While unusual, the Pentagon does sometimes accept gifts from donors, but they normally must be given to fund specific projects, such as a school, hospital, library, museum, or cemetery.

Critics questioned why the US military would accept anonymous funds.

"Using anonymous donations to fund our military raises troubling questions of whether our own troops are at risk of literally being bought and paid for by foreign powers," said Delaware Senator Chris Coons, the top Democrat on the Senate's defense appropriations subcommittee.

By Hannah Pantos

Two Democrats – Senator Jeanne Shaheen and Independent Senator Angus King of Maine – voted in favour of its final passage. Schumer voted “no”.

On Thursday, he announced he would vote to allow the measure to move forward, saying although it wasn’t a bill he liked, he believed triggering a shutdown would be a worse result.

Democrat Party infighting exposes struggle to unite against Trump

Representative Alexandria Ocasio Cortez called Schumer’s willingness to let the spending bill proceed a “huge slap in the face”, adding that there is a “wide sense of betrayal” among the party, according to the BBC’s US partner CBS News.

She said supporting the bill “codifies the chaos and the reckless cuts that Elon Musk has been pursuing”, and that Senate Democrats who voted yes would be empowering “the robbing of our federal government in order to finance tax cuts for billionaires”.

The Democrats had agonised over whether to support the measure, and eventually pushed for a 30-day continuing resolution that was unlikely to earn enough support to pass.

Senator Ted Cruz accused the Democrats of conducting “political theater” and praised the bill’s passage.

“The government is funded, let’s get back to work,” he said in a statement.

The passage is a victory for Trump and congressional Republicans.

On Friday morning, Trump offered rare bipartisan praise of Schumer’s decision to let the bill advance, writing that “a non pass would be a Country destroyer, approval will lead us to new heights”.

The legislation would keep much of the federal funding levels from the Biden Administration in place, with some key changes.

It increases military spending by $6bn (£4.6bn), for items like border security, veterans healthcare, and military spending. But would cut non-defence funding by about $13bn.

Local officials in Washington DC had feared the bill would result in a $1bn cut in federal funds for the city over the next six months. However, the Senate approved a separate bill that kept its current operating budget intact, the New York Times reported.