President Trump on Friday compelled General Motors to manufacture ventilators to help handle the surge of coronavirus patients, using his power under the Defense Production Act.

Trump announced that he’d signed a presidential memorandum requiring the company to “accept, perform and prioritize” federal government contracts for production of the much-needed medical equipment shortly before signing into law a $2 trillion stimulus package to help prop up the economy during this public health crisis.

“Our negotiations with GM regarding its ability to supply ventilators have been productive, but our fight against the virus is too urgent to allow the give-and-take of the contracting process to continue to run its normal course,” Trump said in a statement. “GM was wasting time. Today’s action will help ensure the quick production of ventilators that will save American lives.”

At the White House’s daily news briefing on its coronavirus response, Trump named economist Peter Navarro, currently serving as a trade adviser to the president, to oversee enforcement of the Defense Production Act.

Navarro described the policy as “the most significant industrial mobilization since World War II.”

“We have a wartime president fighting an invisible enemy and we have the full force of government coupled with the full power of private enterprise bearing down on this problem,” he said.

Navarro said that other companies were being cooperative, but the White House had “run into roadblocks” with GM. Trump said there’d been a disagreement over price.

GM responded that i’ts been “working around the clock for weeks to meet this urgent need” and that its commitment to build the ventilators “has never wavered.”

“We are proud to stand with other American companies and our skilled employees to meet the needs of this global pandemic,” said Mary Barra, GM’s chairman and CEO.

Trump had hinted earlier in the day via tweets that he might take the action, writing what seemed like an order that GM start making the ventilators, but he did not then explicitly state that he was invoking the Korean War-era law.

“As usual with ‘this’ General Motors, things just never seem to work out,” Trump tweeted. “They said they were going to give us 40,000 much needed Ventilators, ‘very quickly’. Now they are saying it will only be 6000, in late April, and they want top dollar.”

“Always a mess with Mary B.,” he added, referring to Barra, the company’s chief executive.

“Invoke P,” Trump said in the tweet.

In a subsequent tweet, he explained that “Invoke ‘P’ means Defense Production Act!”

Trump continued to rail against GM and also brought Ford, another automaker, into the mix in another tweet.

“General Motors MUST immediately open their stupidly abandoned Lordstown plant in Ohio, or some other plant, and START MAKING VENTILATORS, NOW!!!!!!” he wrote. “FORD, GET GOING ON VENTILATORS, FAST!!!!!!

Trump has faced sharp criticism from New York Gov. Andrew M. Cuomo (D) among others for not doing more to facilitate the availability of ventilators to areas hit hard by the virus. Just Thursday night, Trump cast doubt on whether Cuomo’s assertion that his state, which has become the epicenter for the coronavirus outbreak in the United States, will need 30,000 ventilators to properly care for the influx of patients anticipated to flood hospitals in coming weeks.

In a subsequent tweet, Trump claimed without citing evidence that ventilators sent to New York had been found in storage.

He also hinted at forthcoming announcements about arrangements with other companies.

“We have just purchased many Ventilators from some wonderful companies,” Trump said in another tweet Friday. “Names and numbers will be announced later today!”

Trump’s tweets drew rebukes from Democrats, including Sen. Sherrod Brown (D-Ohio), who noted in a tweet that General Motors had sold its idled plant in Lordstown in his home state last year to an electric truck maker.

“If the President cared about its former workers, he would know that,” Brown tweeted. “Instead of throwing a tantrum on Twitter, why don’t you just invoke the DPA?”

Brown’s call to invoke the Defense Production Act echoed those of many Democrats — including House Speaker Nancy Pelosi (D-Calif.) — who have questioned why Trump hasn’t used the measure more aggressively.

In recent days, Trump has said the act has provided strong leverage as he talks to private companies about voluntarily making products needed for the response to the pandemic.

“Mr. President, you have the power to order GM and thousands of other companies to start making ventilators, masks, and tests,” Sen. Chris Murphy (D-Conn.), another lawmaker who responded to Trump, said in a tweet. “Stop whining. Use the powers Congress has given you. NOW. Every additional day you wait costs countless lives.”