Chilean doctors successfully separated conjoined twin girls early Wednesday after a marathon 18-hour surgery widely followed in the South American country on television and the Internet.

The 10-month-old twins Maria Paz and Maria Jose are in stable condition even after losing a lot of blood and they are resting in the intensive care unit at Luis Calvo Mackenna Hospital, chief surgeon Francisco Ossandon said.

Parents Jessica Navarrete and Roberto Paredes kept an anxious vigil at the hospital in Santiago as doctors separated the twins at the thorax, stomach and pelvis. It was the seventh and most complex operation yet for the twins.

"Both were successfully separated," Ossandon said at a news conference. "We had a number of difficulties during the surgery, there were some surprises, but we were able to fix, solve the problems."

He added that the twins came out of the surgery in "good condition." Ossandon, however, didn't rule out future complications involving the effects from anesthesia and possible infections.

Navarrete said she was waiting for "a miracle from God" when the high-risk operation began Tuesday morning.

The Chilean twins presented a particularly difficult challenge because they were born sharing many of the same internal organs and even urinary system. About 100 people participated in the procedure, including 25 surgeons and anesthesiologists.

Perhaps providing some comfort to the parents was the hospital's history with conjoined twins. Staff there have separated three sets before. A fourth set, however, died during surgery due to cardiac complications.

According to the University of Maryland Medical Center, one out of every 200,000 live births worldwide results in conjoined twins. About 35 percent survive only one day, while the overall survival rate is 5 percent to 25 percent.

The twins were born in the Villarrica hospital about 470 miles (760 kilometers) from Santiago and were kept under constant medical care, surviving with the aid of an artificial respirator.

Earlier this year, doctors separated the twins' legs, urinary tracts, pulmonary systems and other parts of their bodies.