Former US President Jimmy Carter, 95, is recovering in an Atlanta hospital following a procedure to relieve brain pressure.
The pressure comes from bleeding caused by recent falls, the Carter Center said in a statement.
The procedure was completed without complications at the Emory University Hospital on Tuesday morning local time.
Mr Carter “will remain in the hospital as long as advisable for further observation,” the statement said.
An earlier statement by the Carter Center said the former president was “resting comfortably” and his wife, Rosalynn, was with him.
Mr Carter is the country’s oldest living leader.
The Democrat was the 39th president, serving one term from 1977 to 1981. He was defeated in his re-election bid by Ronald Reagan.
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Since leaving the White House, he has remained active, carrying out humanitarian work with his Carter Center in recent years.
In 2002, he received the Nobel Peace Prize for his work.
In May, Mr Carter underwent surgery for a broken hip after falling at his home in Georgia.
After a separate fall at his home, he made a public appearance at a charity event in October with a black eye.