NEW YORK/WASHINGTON (REUTERS, BLOOMBERG) - Vice President Mike Pence will discuss shortcomings in the US testing for coronavirus infections with governors on Monday (April 20), President Donald Trump said .

His comments came after governors in the states hardest hit by the coronavirus sparred with him over his claims they have enough tests and should quickly reopen their economies amid more protests planned over the extension of stay-at-home orders.

During a White House news conference on Sunday, Trump said his administration will share information with the governors ahead of the Monday call about testing capacity in their states.

He also said he would use the Defence Production Act, a law that allows the government greater power over industrial production in a crisis, to increase manufacturing of swabs used for testing.

The president didn't name the company that would be subjected to the law.

"It should be a local thing," Trump said of testing during a White House news conference on Sunday. "We're going to help them more than a lot," he said of the states.

Pence will "review what more they could do, and do together, to develop locally tailored testing strategies," Trump said.

The White House will "send them a full list of all large lab machinery in the states" and "the potential capacity of those machines if they're fully utilised."

He said some governors are relying on their state laboratories and aren't turning to large commercial and academic labs to expand testing.

Separately, Pence said Sunday the US has enough testing nationwide to allow any state to start lifting lockdown orders, if they have met other criteria.

"We believe we have the testing today around the country, that would allow any state in America to move to phase one (of the recovery plan) if they have met the other criteria," Pence said at a briefing. Those criteria include 14 days of declines in infections and enough hospital capacity to treat everyone who gets sick, he said.

THREE-PHASE PLAN

Governors of both parties have complained they can't begin the White House's three-phase plan to reopen the US economy without far more widespread testing for the virus.

Several governors criticised Trump earlier on Sunday for trying to cast the shortfall in testing as a problem for states to resolve.

"To try to push this off to say that the governors have plenty of testing and they should just get to work on testing, somehow we aren't doing our job, is just absolutely false," Maryland Governor Larry Hogan, a Republican, said on CNN.

Democratic Governor Ralph Northam of Virginia told CNN the idea states have enough tests was "delusional". The region of Maryland, Virginia and Washington DC is still seeing increasing cases.

Trump last week said he had "absolutely" authority to direct states to reopen before backing down and instead issuing guidelines for governors to undertake it.

"Governors wanted total control over the opening of their states" but now want help with testing, Trump said. They "can't have it both ways," he said.

The United States has by far the world's largest number of confirmed coronavirus cases, with more than 740,000 infections and over 40,000 deaths.

It took the United States 38 days after recording its first fatality on Feb 29 to reach 10,000 deaths on April 6 but only five more days to reach 20,000 dead, according to a Reuters tally.

The United States' toll rose to 40,000 from 30,000 in four days after including untested but probable Covid-19 deaths reported by New York City.

New York continued to see hospitalisations decline to 16,000 from a high of 18,000, and the number of patients being kept alive by ventilators also fell on Sunday. There were 507 new deaths, down from a high of more than 700 a day.

"If the data holds and if this trend holds, we are past the high point and all indications at this point are that we are on a descent," Governor Andrew Cuomo said at a daily briefing, while urging residents to continue social distancing.

"We showed you can control the beast. But it's only half time. We still have to make sure we keep the beast down."

To get a baseline of how many people were infected with the novel coronavirus, Cuomo said the state would do the most aggressive anti-body testing in the nation in the next week using a random sample.

New York will test 2,000 people a day or 14,000 per week out of the 19 million residents in the state.

New Jersey reported on Sunday that its new cases rose by nearly 3,900, the most in more than two weeks. Boston and Chicago are also emerging hot spots with recent surges in cases and deaths.

Several states, including Ohio, Texas and Florida, have said they aim to reopen parts of their economies, perhaps by May 1 or even sooner.

The governors of Michigan and Ohio on Sunday said they could double or triple their testing capacity if the federal government helped them acquire more swabs and reagents, chemicals needed as part of the testing process.

Trump's guidelines to reopen the economy recommend a state record 14 days of declining case numbers before gradually lifting restrictions.

Yet the Republican president appeared to encourage protesters who want the measures removed sooner with a series of Twitter posts on Friday calling for them to "LIBERATE" Michigan, Minnesota and Virginia, all run by Democratic governors.

Governor Jay Inslee of Washington redoubled his attacks on Trump's call to "liberate" states, saying the president was encouraging people to violate state laws on self-isolating.

"These orders actually are the law of these states," he said. "To have an American president encourage people to violate the law, I can't remember any time during my time in America where we have seen such a thing."

PROTESTS

Protests demanding an end to stay-at-home measures flared in US states on Sunday.

An estimated 2,500 people rallied at the Washington state capitol in Olympia to protest Democratic Governor Jay Inslee's stay-at-home order, defying a ban on gatherings of 50 or more people.

Despite pleas from rally organisers to wear face coverings or masks as public health authorities recommend, many did not.

In Denver, hundreds of people gathered at the state capitol to demand the end to Colorado's shutdown. As protesters clogged streets with cars, healthcare workers in scrubs and face masks stood at intersections in counterprotest.

Stay-at-home measures, which experts say are essential to slow the spread of the virus, have battered the US economy and more than 22 million Americans have filed for unemployment benefits in the past month.

Demonstrations to demand an end have previously erupted in a few spots in Texas, Wisconsin and the capitols of Ohio, Minnesota, Michigan and Virginia.

"These people love our country," Trump, who has touted a thriving economy as the best case for his re-election in November, told a briefing in Washington on Sunday. "They want to get back to work."

US lawmakers are very close to an agreement on approving extra money to help small businesses hurt by the coronavirus pandemic and could seal a deal as early as Sunday, congressional and Trump administration officials said.

Congress established the programme last month as part of a US$2.3 trillion coronavirus economic relief plan, but it has already run out of money.