A team of surgeons separated conjoined twin girls on Wednesday, but one died just hours later, apparently from a previously detected heart defect.

Surgeons at Guatemala City's Roosevelt Hospital said the 2-month-old girls — who were joined at the sternum, liver and rib cage — were separated after a 12-hour operation.

One of the twins, Angela Corina Pilo, died hours later after suffering cardiac arrest, said Dr. Carlos Manuel Perez, head of the neonatal unit at Guatemala City's Roosevelt Hospital. Her sister, Angela Leticia Pilo, was in intensive care but doing well.

"We have to wait. Now is the most critical stage, from 24 to 48 hours," Perez said.

The girls' parents could not afford the operation and fundraisers — including a dinner held by the wife of President Oscar Berger — were held to cover its cost.

The girls were born June 23 in a village about 60 miles west of the capital.