There are over 53,000 confirmed cases and more than 700 deaths attributed to Covid-19 in the US.
Dr Deborah Birx, of the White House coronavirus taskforce, said the New York City metro area was the source of 56% of all cases and 60% of all new cases in the country. She advised anyone leaving the region to self-quarantine for two weeks.
On Tuesday, Wisconsin, Delaware, Massachusetts, New Mexico, West Virginia and Indiana were introducing stay-at-home orders, bringing the total number of US states under such lockdowns to 17.
Lawmakers on Capitol Hill have been debating the details of an economic stimulus package that could total over $2 trillion (£1.7 trillion).
Democrats and the White House indicated negotiations could conclude on Tuesday, with Treasury Secretary Steve Mnuchin saying “the president wants us to get this done today”.