Senate Minority Leader Harry Reid warned Thursday that Democrats will block any temporary federal spending bill that extends beyond December 2016.

Reid, D-Nev., said he met privately with President Obama in Reno on Wednesday, where the two discussed the matter.

"We are not going to agree to a long-term CR," Reid said, referring to a continuing resolution measure that lawmakers will use to keep the government funded at current levels after the fiscal year ends on Sept. 30.

Reid said Democrats "would probably accept" a short-term bill lasting until Christmas, "but we are not doing anything into the next year and Republicans should be aware of this right now." Reid then called on reporters on the call to inform the GOP leaders in both chambers.

Reid's warning sets up a direct conflict with many conservative groups, who have already been warning against a spending bill that requires the lame-duck Congress to pass a second, long-term spending bill in December.

Conservatives fear that the need to pass another bill would open the door to more deficit spending, and give more power to lobbyist. They warn that Congress at that point will be filled with many lawmakers who won't return next year, and would be voting on legislation without having to worry about being held accountable later by voters.

The GOP-led Congress returns from summer recess next week. House Republicans plan to discuss a short-term spending bill in a closed-door meeting on Wednesday. No decisions have been made on how long the CR should last.

Reid said whether Democrats would agree to the GOP CR depends on whether it adequately funds the government and whether it includes conservative provisions, such as language to exclude taxpayer funding for Planned Parenthood clinics or to defund parts of Obamacare.

Reid called such language, "goofy riders that they normally do, that have nothing to do with anything."