Senator Edward Kennedy (Feb 2008 file photo)

U.S. Senator Edward Kennedy is undergoing further tests at a hospital in the northeastern state of Massachusetts - two days after having a seizure.

A spokeswoman for Kennedy Monday said it is not clear when his doctor will release information about his condition. The 76-year-old Democrat is expected to stay in the hospital for the next couple of days.

Associates of Kennedy said Sunday he was resting, eating and watching sports on television.

Kennedy, who has had health problems in the past, was rushed to the hospital on Saturday after suffering a seizure.

The Massachusetts lawmaker has served in the Senate for more than 45 years, and is the youngest brother of the late President John F. Kennedy, who was assassinated in 1963.

Some information for this report was provided by AP.