WASHINGTON (CNN) -- The House majority whip and the top ranking African-American in Congress is expected to endorse Sen. Barack Obama in the Democratic presidential race on Tuesday, several sources told CNN.
Sources say Rep. James Clyburn will announce Tuesday that he is endorsing Sen. Barack Obama for president.
Rep. James Clyburn has so far been neutral in the race between the front-running Obama and Sen. Hillary Clinton, the former first lady.
But sources close to the South Carolina congressman and high-level Democratic operatives said Clyburn will throw his support to Obama on Tuesday -- the day of the last Democratic primaries, in South Dakota and Montana.
Meanwhile, four of the 17 uncommitted Democratic senators gathered at the party's Senate campaign committee headquarters to discuss their course of action after those primaries. All are party superdelegates whose support will tip the balance of the Clinton-Obama race.
"It was just a dialogue about moving to peace -- how are we going to create unity in the Democratic Party," said Sen. Ken Salazar, D-Colorado, one of the participants.
Another participant, Maryland's Sen. Ben Cardin, said he expected to make a decision in the next few days.
"I think most people realize this process is coming to an end, and it's important to bring this matter to a conclusion," Cardin said. "As I've said all along, I've said my support would be for the person who had the most support, without any specific formula, in the primaries and caucuses and had the momentum going into the general election and has our best chance of winning in November. I think most of the information is known. Just two more states to go."
Most of the 17 will endorse Obama later this week, two sources familiar with the senators' discussions said. But Montana Sen. Jon Tester, who did not attend Monday's meeting, said he was willing to wait until Tuesday's results before making a decision.
"I want to wait until it all plays out in Montana," Tester said. "I think that what's happened over the last couple weeks in Montana and South Dakota has been nothing short of amazing, with Sen. Obama and Sen. Clinton crisscrossing both of those states and giving us the kind of exposure to national candidates like we've literally never had before."
Tester and Cardin were among the Democrats whose 2006 wins gave the party control of the Senate.
Clinton told reporters Sunday after winning the Democratic primary in Puerto Rico that she was taking the presidential race "a day at a time" and is reviewing the "options available" as she moves ahead with her campaign.
Her campaign got a boost from the Saturday ruling by the party's Rules and Bylaws Committee that gives the disputed delegations from Florida and Michigan half their votes.
"People have been trying to get me out of this race since Iowa and my political obituary has yet to be written and we're going forward," she said.
Obama is 46 delegates short of the 2,118 needed to clinch the Democratic nomination, while Clinton needs 202. There are 31 pledged delegates up for grabs in the Tuesday contests, and 202 superdelegates have yet to commit to either candidate.
Obama has the support of 331 superdelegates -- unpledged Democratic elected officials and party leaders. Clinton has 292.
CNN's Kate Bolduan, Ted Barrett and Gloria Borger contributed to this report.