At her first convention-week appearance in Denver, New York Democratic Sen. Hillary Rodham Clinton called upon all the Democrats to support Barack Obama.

"I ask each and every one of you to work as hard for Barack Obama and Joe Biden as you worked for me," Sen. Clinton told the New York delegation at a breakfast hours before the Democratic convention was to formally open in Denver. "We are united, we are together and we are determined."

Clinton criticized Republican presidential candidate John McCain for the ad he launched this weekend.

“I”m Hillary Clinton and I do not approve that ad,” she said. "Let there be no mistake about it: we are united, we are united for change."

In her speech that lasted for about 10 minutes, Sen. Clinton said that Sen. McCain would obstruct Democrats' efforts to end the war in Iraq, reform health care and change the framework of the Supreme Court.

"We've got so much work to do around the world. None of that will happen if John McCain is in the White House," she said.