This third measure is supposed to try to lessen the virus's blow to the economy - at a cost of perhaps $2 trillion, which would be by far the largest immediate price tag for any single piece of legislation in history.
Sen. Mitch McConnell, R-Ky., the majority leader, said he hoped to strike a deal in principle by midnight Friday, an ambitious goal given the wide divergence between the two parties over how to structure a government rescue package unlike anything Congress has contemplated.
"We need to signal to the public that we're ready to get this thing done".
But with Monday's vote deadline looming, a White House official said Republicans would move forward with legislative language even if no agreement was reached on Saturday. He singled out the debate over unemployment as an area where "tremendous" progress has been made thanks to bipartisan support for rebate checks.
Together, the urgent measures represented one of the most dramatic governmental rescue efforts outside wartime, with millions of people thrown out of work, thousands of businesses shuttered, travel severely curtailed and no certainty as to when things might improve.
When one reporter asked Trump what he would tell a anxious nation, the president snapped, "I say that you're a bad reporter".
The top Republican priorities in the bill are "direct financial help" for Americans, relief for businesses, stabilization of the economy and job protection, according to McConnell. Senate leaders say they want to have a final vote to pass the bill on Monday. "But it's essentially unneeded for people who are still working", he said.
But after a second day of marathon closed-door negotiations, there was no sign of an overarching deal between negotiators, despite Republicans' claims of bipartisan agreement on specific issues including unemployment insurance and small business assistance.
"Our hospitals across the country are about to be overwhelmed", said Illinois Sen. The payments would decrease for those making more than $75,000, with an income cap of $99,000 per individual or $198,000 for couples.
But Democrats say McConnell's plan is insufficient, arguing for greater income support for workers and a "Marshall Plan" for the USA healthcare industry, which is preparing for an onslaught of newly sick patients. Mr. Schumer called it "employment insurance" - which he characterized as "unemployment insurance on steroids". Debbie Stabenow (D., Mich.).
Republicans normally hold a slim 53-47 majority in the chamber, short of the 60 votes they need to advance most legislation.
The Phase 3 package also includes $300 billion in small business loans for companies with fewer than 500 employees; a $50 billion bailout for the airline industry; and $150 billion to other industries including hotels, casinos, cruise lines, and shopping malls.
Negotiations over the bill began on Friday. That number would rise to $2,400 in households where two people file income tax joint returns.
Those tax cuts include deferring the payment of the 6.2 percent payroll tax for employers until 2021 and 2022, with half of the payroll obligations for 2020 due by December 31, 2021, and the other half due by December 31, 2022.
The GOP plan would also relax restrictions on telehealth, expand flexible-spending accounts to pay for certain over-the-counter drugs, and boost Medicare reimbursements to providers.
House Speaker Nancy Pelosi, who has been in talks with Mnuchin, returned to Washington on Saturday and was scheduled to join Sunday's meeting.