Washington: Senator Edward M. Kennedy underwent a 3 1/2-hour surgery at Duke University Medical Centre on Monday to remove a malignant brain tumour, the first step in what is expected to be weeks to months of therapy.

The surgery "was successful and accomplished our goals", according to a statement released by the neurosurgeon, Dr Allan Friedman, at the facility in Durham, North Carolina.

Friedman said Kennedy was awake throughout the procedure and should experience no permanent neurological effects from the surgery.

The liberal lion of the Senate, who endorsed Illinois Senator Barack Obama for president in February, said that after completing his treatment, "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."