WASHINGTON (CNN) -- Sen. Tim Johnson of South Dakota, who continues to recover from a brain hemorrhage and subsequent surgery in December, was released from George Washington University Hospital and entered a private rehabilitation facility last week, his office said in a statement issued Tuesday.

Johnson was released from the hospital on Friday, the statement said. The location of the rehabilitation facility was not made public, it said, "to respect the privacy of the senator and his family."

On Dec. 13, after slurring his speech during a talk with reporters, the 60-year-old Democrat underwent surgery for a hemorrhage inside his brain cavity caused by a hereditary condition in which blood vessels are too close together -- called an arteriovenous malformation.

"Senator Johnson had his final angiogram last week which confirmed that there is no evidence of residual arteriovenous malformation," Philip Marion, medial director for the hospital's Department of Rehabilitative Medicine, said in the statement Tuesday.

"The senator made great progress in the two months he spent at GW Hospital and we wish him all the best in his continued recovery."

Johnson will remain in in-patient care, the statement said, to focus on physical, occupational and speech therapy.