Alex Brandon, Associated Press
President Barack Obama pauses as he reads a statement about the death of Sen. Edward Kennedy, D-Mass., Wednesday while on vacation on Martha's Vineyard.

CHILMARK, Mass. — A grieving President Barack Obama paid tribute to Sen. Edward M. Kennedy Wednesday, calling him a colleague, counselor and friend who etched his place in history as a "singular figure" on the American political landscape.

"Even though we knew this day was coming, we awaited it with no small amount of dread," Obama said. "For his family, he was a guardian. For America, he was a defender of a dream."

Wednesday morning's brief remarks by Obama, appearing tieless and coatless outside his rented compound on Martha's Vineyard, were delayed several times as he polished it. Obama had been awakened by a top aide just after 2 a.m. EDT and told of Kennedy's death. He spoke with the senator's widow, Victoria, around 2:25 a.m. and ordered flags flown at half-staff on all federal buildings.

The Massachusetts senator died late Tuesday night after a yearlong struggle with brain cancer. He was 77.

"His fight has given us the opportunity we were denied when his brothers John and Robert were taken from us: the blessing of time to say thank you and goodbye," Obama said.

White House aides said that Obama plans to attend and speak at services for Kennedy, who will be buried near his slain brothers at Arlington National Cemetery, according to an Associated Press source who spoke on condition of anonymity because the plans have not yet been made public.

The White House said there were no plans for Obama to visit the Kennedys at their compound on nearby Cape Cod. Instead, Obama took his family to a private beach after his remarks.

The president called Kennedy "the greatest senator of our time."

But probably Kennedy's greatest gift to Obama came during last year's presidential race. Kennedy, and his niece Caroline, shook up the Democratic establishment in January 2008 when they endorsed Obama over Democratic rival Hillary Rodham Clinton at a critical point in the marathon primaries. Kennedy lit up the Democratic base with his comparisons of the young contender Obama and former President John F. Kennedy.

Then, risking his own health nearly exactly one year before his death, Sen. Kennedy traveled to the Democratic National Convention in Denver, where Obama accepted the presidential nomination, to give a rousing speech on Obama's behalf. The senator also returned to the Capitol in January to see Obama sworn in as the nation's first black president, suffering a seizure at a celebratory luncheon afterward.

Obama called it "momentous support in my race for the presidency."

Obama pointed out many people — seniors, children, families — whose lives have been improved by Kennedy's work on key legislation. Many can now "pursue their dreams in an America that is more equal and more just," Obama said, "including myself."

"His extraordinary life on this Earth has come to an end. The extraordinary good that he did lives on," he said.

In Washington, Vice President Joe Biden scrapped planned remarks at the Energy Department event to talk at length — fighting tears the whole time — about his friend and colleague of many decades in the Senate.

"I truly, truly am distressed by his passing," Biden said haltingly. "I don't think we shall ever see his like again."

Kennedy had been away from the Senate for much of this year, leading to speculation about the impact of his absence on Obama's health care proposals.

Obama last met with Kennedy in late April, when he signed a $5.7 billion national service bill that carries the senator's name. The pair spoke on June 2 about health care overhaul and again on July 10, after Obama personally delivered a letter from Kennedy to Pope Benedict XVI.

Associated Press writer Laurie Kellman contributed to this report.