BELEM, Brazil -- Doctors at a hospital in northern Brazil on Thursday said they were studying how to separate male twins who were born joined at the chest after preliminary examination showed they shared the same heart.

Maria do Carmo Lobato, assistant director of the hospital in Belem, capital of the northern state of Para, was quoted as saying the boys were born on Thursday morning by Caesarian section without complications.

Doctors carried out more tests on Friday to determine how to proceed, the medical team handling the case told a news conference.

The hospital said the mother of the boys had asked not to be identified.