Siamese twins Anastasia and Tatiana Dogaru recover in the intensive care on Thursday after the world's first attempt to separate them. The sisters underwent 12 hours of surgery in the first major intervention out of a series of procedures designed to separate their congenitally united heads.

The surgery ended at 21:00 PM (Cleveland time). The Rainbow Babies and Children hospital in Cleveland (USA) hasn't offered any official information yet.

According to Associated Press, the girls are closely monitored and no news are expected until Friday, when the firs medical bulletin is scheduled. Over 100 doctors are involved in the intervention.

The Romanian twins were already subject to two interventions designed to separate some of the blood vessels in their connected areas.

The case is even more difficult given the fact that one of the girls doesn't have any kidneys, depending entirely on her sister's functions.