President Donald Trump's administration clashed with state governors Sunday over lifting coronavirus lockdowns, in a standoff embittered by his support for protests against the restrictions.

Vice President Mike Pence said that every US state has the ability to do enough testing to allow preliminary re-opening of the economy and a partial restart of normal life in America.

But some state governors said testing capacity was far behind levels needed to avoid sparking new outbreaks of the virus.

The United States has so far recorded 735,000 coronavirus cases -- the highest number of any country -- and registered 39,000 deaths.

"We believe the testing that we have today... once we activate all of the labs that can do coronavirus testing, is sufficient for any state in America to move into phase one," Pence told FOX News Sunday.

"Phase one" ends stay-at-home restrictions for healthy people, and allows restaurants, cinemas, sporting venues, places of worships and gyms to re-open with physical distancing.

"We have every confidence that we can have a sufficient amount of testing to be able to re-open America," Pence said, vowing to double the numbers of tests.

But Virginia Governor Ralph Northam pushed back at the Republican administration's claims that there was enough testing, saying "that's just delusional."

Protesters rally in downtown San Diego against California's stay at home order to prevent the spread of the novel coronavirus, on April 18, 2020
Protesters rally in downtown San Diego against California's stay at home order to prevent the spread of the novel coronavirus, on April 18, 2020 AFP / ARIANA DREHSLER

Gretchen Whitmer, Democratic governor of Michigan, said "we could double or even triple the number of tests that we're executing daily if we had the swabs and reagents" and called for more federal government help.

As the US struggles to quell the mounting death toll, political battle lines are also being drawn ahead of the November election as Trump seeks to reduce damage to his chances of holding onto office.

Anti-lockdown protests have sprung up in several US cities in recent days, with support from Trump who in tweets has called to "LIBERATE" Michigan, Minnesota and Virginia -- all states with Democratic governors -- from stay-at-home orders.

"Our president, obviously, has been unable to deliver on tests. Now he has chosen to focus on protests," Northam told CNN's "State of the Union."

Jay Inslee, the governor of Washington state, also a Democrat, went further still: "To have an American president to encourage people to violate the law... it is dangerous.

But even the Republican governor of Maryland, Larry Hogan, said Trump's encouragement of protesters who picketed the colonial-era statehouse in Annapolis a day earlier was "not helpful."

"To encourage people to go protest the plan that you just made recommendations on, on Thursday, it just doesn't make any sense," Hogan told CNN.