Former Vice President Joe Biden leads other candidates for the Democratic presidential nomination, while several others appeared to be gaining momentum in their bid for the White House, according to a Reuters/Ipsos national opinion poll released on Thursday. The Jan. 22-23 online poll showed that 24% of registered Democrats and independents supported Biden, while 20% backed U.S. Senator Bernie Sanders and 12% said they would vote for U.S. Senator Elizabeth Warren. Another 10% supported former New York City Mayor Michael Bloomberg, 7% picked former Mayor Pete Buttigieg of South Bend, Indiana and 3% backed U.S. Senator Amy Klobuchar.