Senator Hillary Clinton greets supporters as she suspends her campaign for president. ((Associated Press/Ron Edmonds)) Hillary Clinton asked her supporters to give their full backing to former rival Barack Obama as she officially ended her bid for the White House on Saturday.

"This has been a tough fight, but the Democratic party is a family and now it's time to restore the ties that bind us together," she told cheering supporters at the National Building Museum in Washington.

"Today as I suspend my campaign, I congratulate him on the victory he has won, the extraordinary race he has run and and I throw my full support behind him — and I ask all of you to join me in working as hard for Barack Obama as you have for me," she said.

She said she and Obama have faced each other in 22 debates and she has had a "front-row seat to his candidacy" and has seen "his determination, his grace and his grit."

With daughter Chelsea and husband — former U.S. president Bill Clinton — along with her mother, Dorothy Rodham, watching, the New York senator formally ended her bid for the country's highest political office after a 16-month contest to win over party delegates.

The official announcement came less than a week after the Illinois senator secured enough delegates — totalling 2,118 — to clinch the Democratic presidential nomination.

Of roughly 37 million Democrats who voted, about 18 million supported the former first lady.

"Although we weren't able to shatter that highest, hardest glass ceiling this time, thanks to you, it has about 18 million cracks in it and the light is shining through like never before," she said in formally ending her quest to become the first female U.S. president.