WASHINGTON--Amid cries of "We want Jimmy" from weeping supporters, President Carter conceded defeat last night in the face of a landslide loss to Ronald Reagan.

"The American people have made their choice, and I accept it--but not with the same enthusiasm I did four years ago," Carter told the more than 10,000 shocked people who crowded the grand ballroom of the Sheraton Washington Hotel.

Carter pledged to aid the former California governor in the coming weeks, saying he hopes this will be the "best transition ever." Carter added that he had sent a telegram to Reagan congratulating him on a "fine victory," and he called on the nation's citizens to "come together as a united people" to aid his successor.

Against the background of a huge American flag, the president appeared on the podium with his wife, Rosalyn, members of his Cabinet, and senior staff.

The president looked tired, and his voice choked when he spoke of being the most "fortunate" of presidents for having the aid of Vice President Mondale.

Most of the senior administration and campaign officials refused to comment on the president's defeat.

Zbigniew Brzezinski, the president's national security adviser, said he was "shocked" at the loss, adding, "I was very surprised."

Jesse Jackson, the civil rights leader who campaigned extensively for the president, predicted that Reagan's victory will result in the "racial polarization of the nation."

Jackson added that he interpreted the vote as "an appeal to base racial instincts," noting liberal Senate losses across the nation.

The Carter campaign had rented the ballroom from 8 p.m. through the night, but by 8:15 when all three major networks had predicted that Reagan would carry the industrial states of Michigan, Illinois and Pennsylvania, the party was already over.

"I refuse to believe it," Mary Ann McGregor, a Carter volunteer from Baltimore, said as she watched the early returns being broadcast over one of the video screens stationed in each corner of the ballroom.

After the Pennsylvania prediction, redeyed volunteers handed out "Re-elect Jimmy Carter" posters to all who would accept them and the band struck up "Georgia on My Mind."

By 9 p.m., when word spread through the crowd that the president would arrive shortly, the crowd pressed toward the podium, the band began to play "Happy Days are Here Again"--but there were few dry eyes in the room