Carolyn Kaster, Associated Press
White House press secretary Josh Earnest speaks during the daily news briefing at the White House in Washington, Monday, Dec. 14, 2015. Earnest discussed White House meetings with Muslim and Sikh leaders and other topics.

WASHINGTON — Republican demands to end the ban on exporting crude oil emerged as a final negotiating point Monday as lawmakers scrambled to complete a year-end spending bill needed to keep the government running.

In return for lifting the 4-decade-old ban, Democrats were seeking various environmental concessions, including permanently extending tax credits for solar and wind energy production and reviving an environmental conservation fund. Democrats also were trying to block GOP efforts to roll back Obama administration environmental regulations, with Democratic lawmakers who traveled to the Paris climate talks returning energized to fight harder on such issues.

"There's been just a tremendous amount of Democrat pushback on all of the environmental provisions and other provisions too just across the board," Republican Sen. John Hoeven of North Dakota said in a phone interview.

Hoeven said he was hopeful the provision lifting the crude oil ban would survive last-stage talks. "I continue to be optimistic and we'll continue to work to get it," he said.

At the White House Monday press secretary Josh Earnest said: "Completion of the agreement would be hastened if we got Republicans to relinquish their insistence about the inclusion of ideological riders in the budget agreement." He refused to weigh in on inclusion of the oil export ban provision, which the White House has threatened to veto as a stand-alone measure.

Government funding runs out Wednesday at midnight, but Congress may need to pass another short-term extension of a day or two to complete work on the $1.14 trillion government-wide spending bill. Negotiations have dragged on as the legislation has become an increasingly complex grab-bag for priorities and trade-offs large and small.

It's also intertwined with another massive bill extending dozens of tax credits benefiting interest groups across the political spectrum, sparking intense lobbying on numerous fronts.

The legislation may not be finalized until Tuesday, which would probably mean final congressional passage toward the end of the week. Lawmakers would then head home for the holidays, having done their necessary work in typically messy and last-minute fashion.

The ban on exporting crude oil was instituted during energy shortages of the 1970s but Republicans, and some Democrats, say it's long outlived any usefulness. They note a boom in domestic energy production. Environmental groups and most Democrats counter that the main beneficiaries would be big oil companies.

Various agreements were falling into place on the tax bill, according to lobbyists following the talks, including tentative agreement to postpone start of the so-called "Cadillac" tax on high-value health insurance plans under President Barack Obama's health law from 2018 to 2020. There may also be a two-year pause in the existing 2.3 percent medical device tax, which is opposed by lawmakers in both parties.

But there was still significant uncertainty over the fate of those provisions and others and it was possible Congress could opt for more modest two-year extensions of most existing tax credits rather than a major package with permanent and long-range changes.

Associated Press writer Alan Fram contributed to this report.