WASHINGTON — President Donald Trump upped his attacks on the Federal Reserve on Wednesday, demanding the central bank slash interest rates to zero, or even push them into negative territory, claiming that he wants this change to make it cheaper to refinance government debt.

Trump has complained for weeks that some European governments have adopted negative interest rates, and he has said this is unfair and disadvantages the U.S. economy. But Wednesday was the first time he called for the Fed to do the same, pushing what would be an extraordinary policy change that could unleash unknown forces in the U.S. economy.

His directives were delivered in a series of early morning tweets and came with an extra dose of vitriol for Federal Reserve officials. He called them “boneheads” for not moving more quickly to lower interest rates at a time when he said there was low inflation. The Fed has five governors on its board. Trump has appointed four of them, including Chair Jerome Powell, who has been the focus of many White House attacks.

“The USA should always be paying the lowest rate," Trump tweeted. “No Inflation! It is only the naïveté of Jay Powell and the Federal Reserve that doesn't allow us to do what other countries are already doing. A once in a lifetime opportunity that we are missing because of ‘Boneheads.’ ”

Trump's tirade comes on the heels of a disappointing jobs report and a week before the Fed board's next meeting, where officials will decide whether to cut rates. Trump has tweeted dozens of times in the past month about his Fed grievances, stepping up calls that it slash the funds rate as recession fears have grown, but central bank officials remain divided on whether even a modest cut is warranted.

In July, the Fed cut the benchmark interest rate for the first time in more than a decade, lowering it by a quarter point to just below 2.25%. At the time, Powell said the central bank would do whatever it takes to “sustain the expansion," but he stopped short of committing to further reductions.

The last time the Fed cut rates to zero was during the Great Recession, and it has never adopted negative rates.

“The president is calling for what essentially are emergency monetary policy measures at a time when unemployment is at a 50-year low, the U.S. economy is doing better than its peers and is still growing,” said David Wessel, director of the Hutchins Center on Fiscal and Monetary Policy.

The president’s call to refinance the nearly $17 trillion outstanding public debt also is oddly timed. Since the 2008 financial crisis, the government already has extended the average maturity of its debt to more than 69 months from around 48, according to the Treasury Department. The current repayment length is above the average over the past 40 years and near the historic high reached in 2001.

As investors have grown more nervous about the global economy, they have poured money into U.S. treasuries, seeking the assurance of a guaranteed return and liquid markets. That has driven the federal government’s borrowing costs to near-record lows: just 1.7% interest to borrow money for 10 years and just 2.2% for 30-year funding.

In the early 1980s, by contrast, the government paid almost 16% for 10-year money.

Just last month, the Congressional Budget Office reduced by $1.4 trillion its estimate of the interest payments the federal government will make over the next decade, saying it expected borrowing costs will be lower than it projected in May.

Government debt, now at a historic high, has risen by more than $2 trillion on Trump’s watch and is expected to grow by an additional $12 trillion over the next decade, according to CBO. That’s because the government is spending much more than it brings in each year through taxes. The Republican-authored 2017 corporate and personal income tax cut and big spending increases from Congress in recent years have widened the budget deficit, which is projected to exceed $1 trillion this fiscal year.

“We should be focusing more on reducing that debt by looking at what’s creating that debt rather than at refinancing that debt,” said William Hoagland, senior vice president of the Bipartisan Policy Center and a former Republican staff director of the Senate Budget Committee. “This is a clever way of avoiding talking about the real issue.”

The tweets also suggest Trump’s growing unease over the strength of the U.S. economy — his central argument for re-election in 2020. On Tuesday, a Washington Post-ABC News poll found that Trump’s approval rating has slipped as six in 10 Americans now expect a recession within the next year. Trump attacked the results in later tweets Wednesday, calling it a “phony suppression poll.”