Medical personnel from Riverside (CA) University Health Systems hospitals administer a Coronavirus Test to an individual during drive-through testing in the parking lot of Diamond Stadium, March 22, 2020 in Lake Elsinore, California.

Major groups representing U.S. mayors, county executives, police and fire chiefs and first responders are urging President Donald Trump to use a federal act — which he so far has refused to tap — to get them "essential personal protective equipment" quickly to help them respond to the coronavirus pandemic.

"Our nation's first responders call on you to address the shortage of essential personal protective equipment needed to keep them healthy and safe while on the job," the groups wrote in a letter to Trump.

"If we lose emergency personnel to the disease, we cannot transport people to hospitals and protect our citizens," they said.

The groups explicitly asked Trump in that letter to "use the full force and authorities of the Defense Production Act right now to assure they have the critical equipment and supplies they need."

But Trump has resisted calls to use that act to compel companies to produce and ship critically needed items amid the coronavirus outbreak, including PPEs, or personal protective equipment.

"We're getting what we need without putting the heavy hand of government down," said White House trade advisor Peter Navarro at a briefing Sunday.