The United States is on track to "soon" have tens of thousands of new ventilators to treat coronavirus victims, Donald Trump said Thursday evening, but he was vague on the exact timing of those being fielded ahead of an expected surge in cases and deaths.

"We have over 100,000 ventilators being built right now or soon to be started," Mr Trump.

Mr Trump often promises things on a vague time table, usually "two weeks."

The president has pushed companies like GE and others to begin making the breathing devices, saying he has stopped short of using the Defence Production Act to compel them to do so. Democrats have howled that he hasn't done so; he contends the mere threat gives him "leverage" to cut deals.

Andrew Cuomo, New York's Democratic governor, said last week his state's biggest need was "ventilators, ventilators, ventilators" – up to 40,000.

But the president, despite pushing companies to build them, has cast doubt on such pleas. That, however, was before he said as many as 100,000 Americans might die from the easily transferrable disease.