WASHINGTON – Congress will most certainly miss its Friday deadline to wrap up an omnibus spending package to fund the government, and the stalled talks on that measure led to a testy environment Tuesday on Capitol Hill.

While Republican leaders in both chambers said members should prepare for weekend work to finish the year-end legislation, the political schedule was also taking a hit. Organizers for a big-ticket fundraiser for the Republican National Committee called off their Wednesday event because Speaker Paul Ryan, R-Wis., had to pull out of being its headliner. Ryan had committed to the RNC Presidential Trust Dinner in New York City, a major conduit for cash headed to the eventual 2016 presidential nominee.

Meanwhile, the chambers remained deadlocked over several policy provisions to the omnibus.

The top Senate Democratic appropriator, Barbara Mikulski of Maryland, said "40 or 42 poison-pill riders" are giving senior negotiators headaches, including provisions targeting abortion, campaign finance restrictions and a National Labor Relations Board ruling.

Also causing trouble, according to the Maryland Democrat, is the package of tax extenders, which she said is currently "linked" to the catchall agreement.

"We have about 40 or 42 poison-pill riders, but some are really big — Hobby Lobby, campaign finance reform — things that should have never even been on the appropriations," Mikulski said. "So we're kind of stuck at the riders stage."

House Republican leaders planned to advance a short-term continuing resolution to fund the government for a few days beyond Friday's deadline.

The Senate's No. 2 Democrat warned Tuesday of dire consequences if Republicans force language on abortion into the omnibus and said he wouldn't be surprised if the debate runs up through Christmas Eve.

"Just heard about it for the first time today, and if they try to do it, all hell will break loose," Minority Whip Richard Durbin said of the provision. "You can imagine. The phrase 'Hobby Lobby' perks up the ears of many members of the Senate."

A Democratic aide said the Hobby Lobby reference, invoking a Supreme Court decision, was to a pair of provisions already contained in the House's Labor-HHS-Education spending plan. Those involve an employers' exercise of a conscience clause if they believe providing certain health care violates their religious beliefs and language on abortion nondiscrimination.

The biggest campaign finance rider under discussion would relax limits on coordination between political parties and their candidates. Progressive groups and Democratic lawmakers, as well as conservatives in the House Freedom Caucus, are fighting the language.

Rep. John Sarbanes, D-Md., who has been leading the effort against the rider, said the provision would allow big-money donors a new avenue — through the party committees — to give large sums to help their favored candidates.

Supporters of the rider, including its patron, Senate Majority Leader Mitch McConnell, R-Ky., argue it would help party committees keep pace with super PACs and other outside groups.

Other major riders include a House-passed measure that would require the FBI to sign off on all refugee resettlement applications from Syrian and Iraqi asylum seekers.

President Obama has threatened to veto the legislation, which his administration has called "untenable."

Mikulski also indicated that provisions weakening the Dodd-Frank financial regulatory law were gumming up the works.

Earlier in the day, members of the conservative House Freedom Caucus said they would push Ryan for a six-week continuing resolution in order to avoid the kind of end-of-the-year Christmas tree bill that often passes with lawmakers eager to get home for the holidays.

"We've had conversations with Paul already about that," said HFC Chairman Jim Jordan, R-Ohio. "A lot of times when deadlines come around here, we don't always like the decisions that get made."

Still, the Christmas cheer wasn't totally absent from the halls of Congress. Senators took part in their annual Secret Santa party, organized by Sen. Al Franken, D-Minn.

Exiting the Senate Secret Santa with a cheese board shaped like Texas and some Cabot cheese from Democratic Sen. Patrick Leahy of Vermont, Majority Whip John Cornyn, R-Texas, said "I'm hoping people drink a little more eggnog" to advance the discussions on tax extenders legislation.