Donald Trump threatened an American manufacturing firm after it resisted a request from his administration to export millions of protective masks from its Singapore hub to the US to help with the fight against the coronavirus.

The White House had reportedly tried to force 3M, a Minnesota-based firm that produces protective and healthcare equipment, to send some 10 million N95 respirator masks from its plant in Singapore to the US, the Financial Times reported.

The company resisted the request because it would have caused a shortage for medical workers in Asia markets, the report said. Hospitals across the world are facing severe shortages of protective equipment, which puts medical staff at greater risk as they treat coronavirus patients. In the US, many doctors and nurses are re-using their masks every day.

“We hit 3M hard today after seeing what they were doing with their Masks. ‘P Act’ all the way,” Mr Trump wrote on Twitter. “Big surprise to many in government as to what they were doing — will have a big price to pay!” he added.

The president appeared to be referring to the Defence Production Act, a Korean War-era law which allows the White House to compel US companies to sell to the government or switch production to vital supplies in the national interest. It is only the second time the act has been invoked since the pandemic began.

In a statement, 3M said the Trump administration had requested the company “increase the amount of respirators we currently import from our overseas operations into the US. We appreciate the assistance of the Administration to do exactly that.”

It added that the White House had asked the company to limit exports of protective equipment manufactured in the US to Canada and Latin America, which the company opposed on “humanitarian grounds.”

“There are, however, significant humanitarian implications of ceasing respirator supplies to healthcare workers in Canada and Latin America, where we are a critical supplier of respirators. In addition, ceasing all export of respirators produced in the United States would likely cause other countries to retaliate and do the same, as some have already done,” the statement said.

“If that were to occur, the net number of respirators being made available to the United States would actually decrease. That is the opposite of what we and the Administration, on behalf of the American people, both seek.”