WASHINGTON (AP) _ The National Zoo's only African elephant was euthanized Tuesday after veterinarians determined she was too sick to go on.

Nancy, 46, had numerous health problems including a bone infection and fluid buildup in her abdomen. Last week, Nancy began refusing to take her oral medicine.

Nancy arrived at the National Zoo from East Africa in 1956. In her prime she weighed 10,000 pounds, making her the zoo's largest animal.

``She had a wonderful long life at the National Zoo and she was a favorite among zoo visitors,'' zoo director Lucy Spelman said in a statement.

The zoo closed the Elephant House Tuesday, though officials expected it to reopen Wednesday morning.

A necropsy was being performed. Officials then planned to cremate the remains, though they said they would keep the tusks at the zoo.