Maryland Democratic Sen. Barbara Mikulski says congressional leaders are nearing a vote on a spending package to keep the government open.

Story highlights

Congressional negotiators are nearly finished hammering out a new spending package

The agreement will head off a potential government shutdown

Lawmakers must pass a funding measure by Thursday to keep the government open

Washington CNN  — 

Key congressional negotiators have all but finalized a giant government spending bill that must pass by Thursday to avoid a government shutdown.

Senate Appropriations Committee Chairman Barbara Mikulski said Monday she and her House Republican counterpart, Rep. Hal Rogers of Kentucky, “have come to closure” in their negotiations over the $1 trillion bill. But she said there are “other issues,” with the bill, which she did not specify, that are being ironed out by the top House and Senate leaders of both parties.

“When those are resolved we’ll file the bill and be ready to go,” she said.

The bill would fund most of the government through September but money for the Department of Homeland Security would run out early next year. That will give Republicans who will then have control of both the House and Senate, an opportunity to pass legislation blocking President Barack Obama’s executive orders on immigration, which they strongly oppose.

House Republicans had planned to unveil a bill Monday night but that appears to now be slipping to Tuesday as those final issues are resolved. A House vote will likely be Thursday, potentially followed later that day by with a Senate vote.

“I believe we will not a have a shutdown,” Mikulski, a Democrat from Maryland, told reporters.

Republican leaders in the House and Senate have also said there won’t be a shutdown, even though some conservatives lawmakers would like to force the immigration issue before Congress adjourns in a few days.

House and Senate Democrats have warned Republicans they will vote against a final spending bill if it contains what they consider onerous policy riders restricting the Environmental Protection Agency or other federal agencies. Mikulski, who has spearheaded negotiations over the bill for her party, said those riders are not the issues the House and Senate leaders are negotiating over now.