Surgeons have separated a pair of twin boys who were conjoined at the head in what they have hailed as a landmark operation.

The 16-hour surgery on two-year-old brothers Jaga and Kalia was the first of its kind in India. A team of 30 carrued out the operation at a state-run hospital.

The boys, from a village in the eastern Orissa state, were joined at the head – a condition known as craniopagus. They born with shared brain tissue and blood vessels.

Surgeons separated these in a procedure which took more than 18 hours.

They said the most challenging aspect of the surgery was to provide skin that could cover both sides of the brain for the children.

They have now been moved to an intensive care unit and the next steps will involve reconstructing their skulls.

"Both the children have other health issues as well. While Jaga has heart issues, Kalia has kidney problems," neurosurgeon A K Mahapatra told the BBC.

One of the boys who was previously part of a conjoined twin recovering after surgery (AIIMS/AFP/Getty Images)

Indian conjoined twins before their surgery at the AIIMS hospital in New Delhi (AIIMS/AFP/Getty Images)

"Though initially Jaga was healthier, now his condition has deteriorated. Kalia is better," he added.