New York Governor Andrew Cuomo speaks to the press at the Jacob K. Javits Convention Center in New York.

New York Governor Andrew Cuomo said on Tuesday that he would refuse any order by President Donald Trump that would begin the process of reopening the economy before it was safe to do so without reigniting the coronavirus outbreak in his state.

Cuomo and the governors of six other northeastern states said on Monday they would formulate a regional plan to gradually lift social-distancing restrictions that have shut down nonessential businesses and schools. Health officials credit the shutdown with slowing the spread of the virus in New York.

On the Pacific Coast, the governors of California, Oregon and Washington state said they also would take a regional approach, but cautioned that any large-scale reopening would depend on a decline in the rate of spread in their area.

Soon after the announcements, Trump asserted he had the ultimate authority to reopen the largely shuttered economy even though he earlier had deferred to state governors in putting social-distancing orders in place.

At a Monday briefing, Trump pushed back against the actions of governors in determining when and how to reopen the economy, saying, "The president of the United States calls the shots." He said they could not do anything without his approval.

"If he ordered me to reopen in a way that would endanger the public health of the people of my state, I wouldn't do it," Cuomo said in an interview with CNN, referring to the president.

Cuomo said any reopening would have to come in phases and take months to complete. Widespread testing was the key to a successful restart, he said.

The New York governor, who has made a point of saying policy should be guided by science and not politics, cautioned that a premature order by Trump would set off a federal clash with the states that would end up in court.'

The wrangling coincides with signs the outbreak has been slowing in New York and other states where it struck early.

Cuomo on Monday said "the worst is over" for New York, the state hit hardest by the novel coronavirus, as hospitalizations appeared to be reaching a plateau and deaths increased by 671, the lowest daily total in a week.

On Monday, the United States reported about 1,500 new fatalities, far below last week's running tally of roughly 2,000 deaths every 24 hours. That brought the U.S. death toll from COVID-19, the highly infectious respiratory disease caused by the virus, to more than 23,600 on Monday, out of more than 582,000 known U.S. infections, according to a Reuters tally.