Secretary of State Hillary Clinton left New York-Presbyterian hospital on Wednesday and was driven away with her husband, Bill, and daughter, Chelsea, and an aide, a Reuters photographer witnessed.
It was unclear where she was going or whether she had been discharged from the hospital, where she had been admitted for treatment of a blood clot behind her right ear.
A hospital spokeswoman directed all questions about Clinton, 65, to the State Department, which had no immediate comment.
Earlier Wednesday, a State Department spokeswoman said Clinton, who had not been seen in public since December 7, had been talking with her staff by telephone and receiving memos.
Clinton also spoke to two foreign officials - the U.N. envoy on Syria and the prime minister of Qatar - on Saturday, the day before the State Department disclosed the blood clot and her stay at New York-Presbyterian Hospital.
"She's been quite active on the phone with staff and taking paper, etc.," State Department spokeswoman Victoria Nuland said at the department's daily briefing.
The State Department announced on Sunday that Clinton was in a New York hospital for treatment of a blood clot that stemmed from a concussion she suffered in mid-December.
The concussion was itself the result of an earlier illness, described by the State Department as a stomach virus she had picked up during a trip to Europe that led to dehydration and a fainting spell after she returned to the United States.
In a statement released by the State Department on Monday, Clinton's doctors said they were confident that she would make a full recovery and that she would be released from the hospital once the correct dosage of blood thinners had been determined.