Saudi doctors managed to separate Monday the lower organs of two infant Polish girls who were born joined at the spine and intestines, a member of the medical team said.

Speaking as the operation went into its fifth hour, Dr. Soud al-Jadaan told a press conference that the team of 50 doctors, technicians and nurses had separated the intestines, urinary systems and sexual organs of the 13-month-old Daria and Olga Kolacz.

"There were no surprises and everything went according to schedule," al-Jadaan said. "It needed a lot of time to split them from the lower part of the bodies ... It was sensitive, but we did it with no complications."

The surgery began after the twins had undergone 20 days of medical tests at King Abdul-Aziz Medical City for the National Guard in the Saudi capital, Riyadh, to confirm that a safe separation was possible. The cost of the operation is being financed by Crown Prince Abdullah, the kingdom's de facto ruler, according to the official Saudi Press Agency.

Crown Prince Abdullah (search) offered to pay medical and travel expenses for the twins and their mother, Wieslawa Dabrowska, after being informed of the case by a Saudi doctor, who learned about the twins from an Internet discussion forum. The family is from Janikowo in central Poland.

The 10-stage operation is expected to last for about 15 hours, it said.

The first stage, general anesthetization, went successfully and took two hours, Dr. Mohammed Jamal, who led the anesthetization team, told the agency. He said the twins were in stable condition.

Before leaving for Saudi Arabia last month, Dabrowska, a 38-year-old headmistress, expressed hope that the operation would end in success. Polish doctors told her that they didn't have experience in such cases.

Monday's operation was the ninth of its kind at the Riyadh hospital. The last one was early last year when doctors successfully separated eight-month-old Filipino conjoined twin girls who shared an abdomen, pelvis and lower organs.

Crown Prince Abdullah paid US $320,000 (euro 235,000) for the surgery and visited the Filipino twins during their recuperation.