WASHINGTON -- House Speaker Paul Ryan (R-Wis.) admitted on Monday that Congress may not meet the December 11 deadline to fund the government.

In an interview with 1380 AM radio in Janesville, Wisconsin, Ryan indicated that Congress could pass a short continuing resolution to keep the government open for a few more days while lawmakers work out differences over the larger omnibus spending package. 

"It might take us more than just this week to get these issues put together correctly," Ryan said of the omnibus and expiring tax provisions. 

Republicans' first offer to Democrats on the omnibus was met with a firm rejection. Democrats wouldn't accept Republicans' anti-environment riders, or pitch to attach legislation it passed last month that would tighten the screening process for Syrian refugees.

Without at least a short-term funding patch passed by the end of this week, the government will shut down.

The House has yet to release any details on a final deal. Former Speaker John Boehner (R-Ohio) may have secured a budget agreement with the White House on his way out -- which sets spending levels and raises the debt ceiling into 2017 -- but it doesn't guard against policy riders when it comes to the minutiae of what will be funded.

As discussions continued over riders, a Republican aide told The Huffington Post not to expect any final omnibus package Monday -- meaning Congress is cutting it close to deadline.