The 15-month-old Indonesian twin sisters who were conjoined at the hip and stomach are said to be recovering well after 16 doctors performed 10 hours of separation surgery in Singapore on Saturday.

The twins were born fused at the stomach and hip and had three legs. After the operation, the sisters have one leg and one arm each and will soon be fitted with artificial limbs.

The girls woke up smiling Sunday. One of them has already been taken off a ventilator and the other will remain on it for another day. The twins will remain hospitalized for up to three weeks.

Conjoined twins occur about once in every 150,000 to 200,000 live births.

Singaporean doctors have experienced mixed results separating conjoined twins.

Some information for this report provided by AP, AFP and Reuters.