US lawmakers have reached a deal for a new package to boost the world's largest economy, which has been battered by the coronavirus pandemic, congressional leaders announced Sunday.

"We've agreed to a package of nearly $900 billion. It is packed with targeted policies to help struggling Americans who have already waited too long," Republican Senate leader Mitch McConnell in a statement.

Democratic House Speaker Nancy Pelosi and Senate minority leader Chuck Schumer confirmed an agreement had been reached with Republicans and the White House on a deal that "delivers urgently needed funds to save the lives and livelihoods of the American people as the virus accelerates."

The package is expected to include aid for vaccine distribution and logistics, extra jobless benefits of $300 per week, and a new round of $600 stimulus checks -- half the amount provided in checks distributed last March under the CARES Act.

Congress was working under a deadline of midnight Sunday -- needing to reach consensus both on assistance to hard-pressed American households and companies and on the 2021 federal budget in order to avoid a government shutdown.

Number two Democrat in the House of Representatives, Steny Hoyer, said he expected the deal to pass on Monday and then head to the Senate.

This would require passage of a stopgap measure by midnight on Sunday to keep the federal government funded an extra 24 hours and avert a shutdown.