After undergoing what his doctors described as a successful brain surgery, a family spokesperson said Senator Edward Kennedy told his wife, "I feel like a million bucks."

Stephanie Cutter noted that Kennedy also joked with his wife, Vicki, "I think I'll do that again tomorrow.''

His doctors had earlier reported good progress following the operation.

"I am pleased to report that Senator Kennedy's surgery was successful and accomplished our goals," Dr. Allan Friedman of Duke University Medical Center said in a statement.

"The surgery lasted roughly 3 1/2 hours and is just the first step in Senator Kennedy's treatment plan. After a brief recuperation, he will begin targeted radiation at Massachusetts General Hospital and chemotherapy treatment. I hope that everyone will join us in praying for Senator Kennedy to have an uneventful and robust recovery."

Friedman is an internationally renowned brain surgeon.

The famed 76-year-old Democratic senator suffered a seizure on May 17 and was later diagnosed with a malignant glioma -- a deadly type of brain tumour.

The Massachusetts senator's office released a statement earlier Monday thanking people for their support.

"I am deeply grateful to the people of Massachusetts and to my friends, colleagues and so many others across the country and around the world who have expressed their support and good wishes as I tackle this new and unexpected health challenge,'' Kennedy said in the statement.

"I am humbled by the outpouring and am strengthened by your prayers and kindness.''

Despite the physical toll associated with the surgery and chemotherapy, the senator said that after the treatment is finished: "I look forward to returning to the United States Senate and to doing everything I can to help elect Barack Obama as our next president.''

Kennedy, considered the leader of the liberal wing of the Democrats, has endorsed Obama for the party's presidential nomination.

Kennedy's past

Edward "Ted" Kennedy is the younger brother of John F. Kennedy, who became the U.S.'s president after winning the 1960 election but was assassinated in November 1963.

Kennedy replaced John as Massachusetts senator. In 1964, a plane crash left him with severe injuries and killed an aide.

Another brother, Robert F. Kennedy, ran for the Democratic nomination in 1968 but was assassinated.

Ted Kennedy delivered the eulogy at Robert's funeral.

Joseph, Kennedy's eldest brother (he was one of nine children), died in an airplane crash during the Second World War.

Kennedy sought his party's presidential nomination in 1980, running against sitting U.S. President Jimmy Carter, but lost.

With files from The Associated Press