The twins, weighing four kilograms, have separate heads, three legs and four hands, but single anus and genital.

The doctors are yet to examine the internal organs of their body.

Salma, 27, gave birth to the twins at about 12:35pm following a caesarean. She was admitted to the hospital on Sunday.

The babies were taken to the Paediatric Surgery Ward immediately after their birth where they have been kept on life support.

Prof Kabirul Islam, head of the department of Paediatric Surgery told the Daily Star that conjoined twins are rare in Bangladesh and even in the world.

"We last received such case in 2004 and managed to separate them, but one of them died straight away due to the toxic element from the other twin's body who also died later," he said.

Dr Kabirul also said that the condition of the newborns is unstable with one of them having breathing difficulties.

On the issue of their separation, he said that if their condition becomes stable within a few days, the doctors would decide whether they could be separated or not following x-rays and ultrasonography tests.

"The twins might also be internally joined, in which case one of them may have to be sacrificed to save the other's life," Dr Kabirul said.

On this type of rare birth, Assistant Registrar of Maternity Department Meher Afroz said that when the embryo is not properly divided or when the twins become linked at the cervix accidentally, they are born as conjoined.

She also mentioned that family history, delayed pregnancy and having birth control pills for long increase the risk of giving birth to such babies, adding that this mother has no such history.

The mother of the twins Salma told The Daily Star that she has two other daughters aged five and two.

Her husband Abu Sayeed is a cloth trader and lives at city's Gendaria.