In a 32-hour marathon operation, doctors have separated two Bangladeshi twins who were joined at the head, the news.com.au portal said on Tuesday.

Doctors at the Melbourne's Royal Children's Hospital were cautiously optimistic about the condition of two-year-old orphans Krishna and Trisha, who shared brain tissue and blood vessels.

"I think everything is going really very well at the moment," Australian tabloid Herald Sun quoted the hospital's chief doctor, Leo Donnan, as saying.

Doctors say, however, that there is a 25%-chance that both girls will survive and 50% probability that they will suffer brain damage. The children still face considerable risks, including blood loss and infections.

The 27-hour operation to separate brain tissues was followed by a five-hour reconstructive surgery, during which doctors assembled the twins' skulls using their skin, bone grafts and artificial materials.

The girls are expected to remain in an induced coma for several days, The Times said.

Donnan said there was "still a long way to go" until the girls are released from the intensive care unit. He added that the first few days after surgery would be crucial.

The girls were brought to Australia by the Children's First Foundation (CFF).

MOSCOW, November 17 (RIA Novosti)