WASHINGTON — Democrats on Wednesday rejected a proposed spending bill deal due to concerns over policy riders Republicans want to attach to the must-pass legislation, leaving congressional leaders with fewer than 10 days to reach an agreement to avert a government shutdown on Dec. 11.

House Minority Leader Nancy Pelosi, D-Calif., met with approximately 100 Democrats Wednesday morning to discuss the offer, which included several policy provisions that would scale back environmental regulations and make it more difficult for refugees from Syria and Iraq to enter the country. Democrats on the Appropriations Committee are moving forward with a counter offer, according to a senior Democratic aide.

Senate Democrats also rejected the offer.

Democrats have warned for weeks that they would not accept a spending bill that includes “poison pill” policy riders like those that would scale back banking regulations or undermine President Obama’s executive actions on climate change.

Democratic leadership aides said the problematic policy riders included in the Republican offer include proposals to:

 Prevent the administration from enforcing Environmental Protection Agency emissions regulations.

Impose a moratorium on allowing Syrian and Iraqi refugees to enter the United States until certain security benchmarks are met.

Lift campaign finance restrictions on coordination between parties and individual candidate campaigns.

If any of those provisions appear in the final omnibus, they would be deal breakers, according to the aides.

Democrats charge that the Republican proposal was not the result of negotiations between appropriators, and Democrats are frustrated that Republican leaders appeared to be working on a deal outside of the talks occurring at the committee level.

House Speaker Paul Ryan, R-Wis., called Pelosi Tuesday night to discuss the offer, which was negotiated by Senate Appropriations Committee Chairman Thad Cochran, R-Miss., and House Appropriations Committee Chairman Hal Rogers, R-Ky., in consultation with Republican leaders, aides said.

“The proposal was an Appropriations Committee offer, constructed by the Appropriations Committee,” said Ryan spokeswoman AshLee Strong. “The speaker supported it, but he’s deferring to Chairman Rogers.”