WASHINGTON >> Tensions flared today as Washington strained to respond to the worsening coronavirus outbreak, with Congress arguing over a nearly $2 trillion economic rescue package and an impatient President Donald Trump musing openly about letting the 15-day shutdown expire.

As the U.S. braces for an onslaught of sick Americans, and millions are forced indoors to avert a spike that risks overwhelming hospitals, the most ambitious federal intervention in modern times is testing whether Washington can swiftly halt the pandemic on the home-front. By evening, it appeared there would be no further votes today, and talks would push into the night.

“It’s time to get with the program, time to pass historic relief,” said an angry Senate Majority Leader Mitch McConnell as he opened the chamber after a nonstop weekend session that failed to produce a deal. “This is a national emergency.”

Fuming, McConnell warned Democrats — pointedly House Speaker Nancy Pelosi — to quit stalling on “political games,” as he described Democratic efforts to steer more of the aid toward public health and workers.

Trump, who has largely been hands off from the negotiations, weighed in late today from the White House briefing room, declaring that Congress should vote “for the Senate bill as written,” dismissing any Democratic proposal.

“It must go quickly,” Trump said. “This is not the time for political agendas.”

The president also sounded a note of frustration about the unprecedented modern-day effort to halt the virus’s march by essentially shutting down public activities in ways that now threaten the U.S. economy.

Even though Trump’s administration recommended Americans curtail activities starting a week ago, the president said: “We cannot let the cure be worse than the problem itself. At the end of the 15-day period, we will make a decision as to which way we want to go.”

“Let’s go to work,” he said. “This country was not built to be shut down. This is not a county that was built for this.”

Trump said that he may soon allow parts of the nation’s economy, in regions less badly hit by the virus, to begin reopening, contradicting the advice of medical and public health experts across the country, if not the globe, to hunker down even more firmly.

Pelosi assailed Trump’s idea and fluctuating response to the crisis.

“He’s a notion-monger, just tossing out things that have no relationship to a well coordinated, science-based, government-wide response to this,” Pelosi said on a health-care conference call. “Thank God for the governors who are taking the lead in their state. Thank God for some of the people in the administration who speak truth to power.”

The White House team led by Treasury Secretary Steven Mnuchin worked on Capitol Hill for a fourth straight day of talks as negotiators narrowed on a bipartisan accord.

In the nearly empty building, the virus continued to strike close. Republican Sen. Rand Paul of Kentucky, who announced he tested positive for coronavirus, is now among five senators under self-quarantine. Several other lawmakers have cycled in and out of isolation. And the husband of Sen. Amy Klobuchar, D-Minn., is in a hospital with pneumonia after testing positive, she said today.

First lady Melania Trump, meanwhile, has tested negative for the coronavirus, Trump said.

With a wary population watching and waiting, Washington labored under the size and scope of a rescue package — larger than the 2008 bank bailout and 2009 recovery act combined.

Democrats are holding out as they argue the package is tilted toward corporations and should do more to help suddenly jobless workers and health care providers with dire needs.

In particular, Senate Democratic leader Chuck Schumer, D-N.Y., wants constraints on the largely Republican-led effort to provide $500 billion for corporations. Democrats call that a “slush fund.”

Yet, he said, “We’re very close to reaching a deal.” Even so, another attempt to move the package forward snagged, blocked as Democrats refused to quit negotiating.

Democrats won one concession — to provide four months of expanded unemployment benefits, rather than just three as proposed, according to an official granted anonymity to discuss the private talks. The jobless pay also would extend to self-employed and so-called gig workers.

But Republicans complained Democrats were holding out for more labor protections for workers, wanting assurances that corporations taking federal aid will commit to retaining their employees.

Pelosi came out with the House Democrats’ own sweeping $2.5 trillion bill, which would provide $1,500 directly to the public and $200 billion to the states, as governors are pleading for aid. She urged Senate negotiators “to move closer to the values” in it.

Trump has balked at using his authority under the recently invoked Defense Protection Act to compel the private sector to manufacture needed medical supplies like masks and ventilators, even as he encourages them to spur production. “We are a country not based on nationalizing our business,” said Trump, who has repeatedly railed against socialism overseas and among Democrats.

From his home, Democratic presidential rival Joe Biden criticized Trump for stopping short of using the full force of emergency federal authority .

“Trump keeps saying he’s a wartime president,” Biden said in an online address. “Well, start acting like one.”

On the economic front, the Federal Reserve announced today it will lend to small and large businesses and local governments as well as extend its bond-buying programs as part of a series of sweeping steps to support the flow of credit through an economy ravaged by the viral outbreak.

Central to the emerging rescue package is as much as $350 billion for small businesses to keep making payroll while workers are forced to stay home. The package also proposes a one-time rebate of about $1,200 per person, or $3,000 for a family of four, as well as extended unemployment benefits.

Hospitals would get about $110 billion for the expected influx of sick patients, said Mnuchin. But Democrats are pushing for more health-care dollars for the front-line hospitals and workers.

The urgency to act is mounting, as jobless claims skyrocket and financial markets are eager for signs that Washington can soften the blow of the health-care crisis and what experts say is a looming recession.

For most people, the new coronavirus causes only mild or moderate symptoms, such as fever and cough. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia. The vast majority of people recover from the new virus. According to the World Health Organization, people with mild illness recover in about two weeks, while those with more severe illness may take three to six weeks to recover.