(Adds comments from Assistant Majority Leader, other details)
WASHINGTON, Dec 20 (Reuters) - U.S. Senate Majority Leader Harry Reid appeared to be feeling better after being hospitalized on Friday with an undisclosed illness, his office said in a statement on the Senate's last work day of the year.
Although the Nevada Democrat was alert and resting, doctors ordered him not to work and remain for observation, Reid's aides said. He missed several key Senate votes as lawmakers wrapped up their work before the holiday break.
"Early this morning, Senator Reid was not feeling well and as a precaution decided to go to the hospital. Tests have been conducted and everything is normal," the Nevada Democrat's office said.
"He is in the hospital today, alert, resting and feeling better," his office later posted on Twitter and Facebook. "Doctors have asked that he remain in the hospital for observation so he will not be working today."
It was not clear when Reid, 74, would be released or what the nature of his illness was. But the Senate's Assistant Majority Leader Richard Durbin said that he had spoken with Reid.
"He sounds hale and hearty and anxious to get home and then back to work," Durbin said on the Senate floor Friday afternoon.
"We look forward to that happening when he returns to this desk early in the new year," Durbin said just before the chamber halted its work for 2013. Senators return for legislative business in early January.
Reid, who was first elected to the Senate in 1986 and became its leader in 2007, suffered a stroke in 2005 and was injured last year when his motorcade crashed in Las Vegas.
In Reid's absence on Friday, the Senate voted to approve John Koskinen, President Barack Obama's nominee to lead the Internal Revenue Service, and Alejandro Mayorkas, Obama's pick for deputy secretary of the Department of Homeland Security.
Obama's nominee to head the U.S. Federal Reserve, Janet Yellen, also advanced on a key procedural vote. The Senate is expected to officially confirm Yellen, currently the Fed's vice chair, on Jan. 6. (Reporting by Susan Heavey; additional reporting by Thomas Ferraro; Editing by Scott Malone, Bernadette Baum and Paul Simao)