US Sen Edward Kennedy, a Democratic icon and a leading liberal voice, endorsed Barack Obama on Monday for the party's presidential nomination and called the young lawmaker an inspirational uniter.

'He is tough-minded but he also has an uncommon capacity to appeal to 'the better angels of our nature,'' Kennedy said, quoting from President Abraham Lincoln's first inaugural address in 1861.

Kennedy, flanked by Obama at an ear-splitting rally of several thousand people at American University, said: 'Every time I've been asked over the past year who I would support in the Democratic primary, my answer has always been the same: I'll support the candidate who inspires me, who inspires all of us.'    

Kennedy invoked the memory of his brother, the slain President John Kennedy, and was joined onstage by the late president's daughter, Caroline, and his own son, US Rep Patrick Kennedy, in backing Obama, the 46-year-old, first-term Illinois senator who could be the nation's first black president.

Supporters lined up for hours beforehand to see members of the nation's most famous political family embrace a candidate whose charisma and youth have drawn comparisons to John Kennedy. Several hundred who could not get in the packed gym waited outside to cheer Obama and young women screamed 'We love you Obama!' from dormitory windows.

Sen. Hillary Clinton of New York, Obama's chief rival, brushed off the Kennedy endorsements while aides noted other Kennedys have backed her to be the party's presidential nominee in the November election.

'At the end of the day this is not about anyone else other than the candidates,' Clinton told reporters in a conference call from Connecticut. 'I have the experience we need to make the changes we want in America.'    

Former Maryland Lt. Gov. Kathleen Kennedy Townsend on Sunday threw her support behind Clinton, who is seeking to be the first woman president. The daughter of former US Sen Robert Kennedy said her brother, Bobby, and sister, Kerry, also supported the former first lady. - Reuters