WASHINGTON (AP) _ President Clinton marked ``a moment of celebration and a moment of sadness'' today, welcoming the World Cup-winning U.S. women's soccer team to the White House and pausing to remember John F. Kennedy Jr., his wife and her sister.

The president and his wife, Hillary, and Vice President Al Gore and his wife, Tipper, joined hundreds of enthusiastic fans on the South Lawn on a sweltering day.

Clinton opened his remarks by speaking of Kennedy, his wife, Carolyn Bessette Kennedy, and her sister, Lauren Bessette, presumed dead in a plane crash.

``We all know this is both a moment of celebration and a moment of sadness for the United States,'' the president said, adding: ``Our thoughts and prayers are with the families of John Kennedy and Carolyn and Lauren Bessette.

``It is at times like this that we really stop to recognize that as big and diverse as our country is, we can come together as a national family,'' he said. ``We can come together in sorrow or in joy if it reflects the values that we honor most. This is one of those moments.''

Saluting the team, Clinton said they had ``brought America to its feet, had us screaming our lungs out with pride and joy.''

``Their triumph has surely become America's triumph,'' he said. ``We are all proud of them.''