Doctors treating prominent U.S. Senator Edward Kennedy say his apparent seizure Tuesday was caused by fatigue.

Kennedy, who has brain cancer, collapsed during an inauguration luncheon in honor of President Barack Obama at the Capitol building. He was taken to a nearby  hospital, where he underwent tests.

Doctors say the 76-year-old liberal icon is awake, talking with friends, and feeling well.  He will remain in the hospital overnight for observation.

Mr. Obama told dignitaries at the inaugural lunch that he was praying for Kennedy, who he called a warrior for civil rights.

Kennedy underwent surgery for a malignant brain tumor last year, after being diagnosed in May.

He has represented the state of Massachusetts in the Senate since 1962 and is the only surviving brother of the late President John Kennedy.