Washington (CNN) -- The U.S. government shut down at 12:01 a.m. ET Tuesday after lawmakers in the House and the Senate could not agree on a spending bill to fund the government. The two sides bickered and blamed each other for more than a week over Obamacare, the president's signature health care law. House Republicans insisted the spending bill include anti-Obamacare amendments. Senate Democrats were just as insistent that it didn't. Federal employees who are considered essential will continue working. But employees deemed non-essential -- close to 800,000 -- will be furloughed. Most furloughed federal workers are supposed to be out of their offices within four hours of the start of business Tuesday.NEW: The House is expected to vote again overnight, including on appointing House negotiators"We will not go to conference with a gun to our head," says Sen. Harry ReidObama says troops will get paid on time, but civilians may get more furloughsConservatives wanted to undermine Obamacare before its private exchanges take effect Tuesday
Earlier, _ had rejected a House proposal by a 54-46 vote, strictly along party lines.