The twins have been separated from the crown of their heads
Doctors have successfully separated two-year-old Egyptian twins joined at the head in a painstaking 34-hour operation at a Dallas hospital.
The team of surgeons told a news conference that the procedure had gone as hoped, but warned Mohamed and Ahmed Ibrahim were not out of danger yet.
They will be kept in a drug-induced coma for several days to reduce brain swelling, and face years of reconstructive surgery on the areas where their skulls had fused together.
Egyptian and Middle East media have closely followed the progress of the operation - the first such procedure since the death of twin Iranian women during surgery in July.
"Things have gone according to surgical plans," said Dr Jim Thomas, chief of critical care at the Children's Medical Center in Dallas, Texas.
"There have been no surprises, and none of the potential complications that surgeons prepared for have occurred."
The World Craniofacial Foundation paid for the boys to come to the Children's Medical Center when they were one-year-olds.
Doctors spent a year assessing the chances of successfully separating them. They carried out tests on the boys and visited the team who operated on Guatemalan twins last year.
"Armed with that, plus some very detailed planning, we felt more comfortable proceeding," said neurosurgeon Dr Kenneth Shapiro, who led the surgical team.
Born by Caesarean section in Qus, Egypt, 2 June 2001
Arrived in Dallas in June 2002
Tissue expanders inserted under skin in April 2003 to prepare for reconstruction
The twins are now in a critical but stable condition
Concerns include the risk of infection and how the wounds will heal
The twins have separate brains, but share a complicated web of blood vessels and circulatory systems that feed the blood to the brain.
The five neurosurgeons completed the most difficult and dangerous part of the operation to physically separate their blood vessels on Sunday morning - about 26 hours after the twins entered the operating theatre.
A team of cranial and facial surgeons were then brought in to repair the damage to their skulls, using tissue from their thighs that had been expanded using balloon-like devices months before surgery.
The entire operation took 34 hours and involved a team of 40 doctors, nurses and other staff.
News of the separation overwhelmed the boys' parents, whose devout faith was said to have kept them going through the ordeal.
"When somebody came up and said 'We have two boys', the father Ibrahim jumped to my neck and he hugged me and he fainted," said the twins' Egyptian doctor Nasser Abdelal.
"He told me that he never dreamed of such a moment".
The boys' relatives and friends in their home town of al-Homr, near the southern Egyptian city of Qus, were praying for a successful outcome.
"If this is true, then this is very good news," the twins' uncle Nasser Mohammed Ibrahim said upon hearing of the separation from Associated Press.
The family decided to go ahead with the operation knowing there was a risk of brain damage or death to one or both of the twins.
The boys faced a lifetime of difficulty if they stayed conjoined
But they said it was the only chance the boys had of a normal life.
Conjoined at the crown of the head since birth, the boys had trouble closing their eyes, moving their necks and swallowing.
They could not stand on their own because of the way they were joined, and would have faced certain and progressive loss of functions had they remained as they were.
They still face years of reconstructive work to repair the top of their heads that will not have bone underneath.
This is the first operation to separate twins conjoined at the head since the deaths of Laleh and Ladan Bijani in July.
The 29-year-old Iranian women died within 90 minutes of each other from massive blood loss during the separation surgery in Singapore.
However, doctors hope that Ahmed and Mohamed's young bones and tissue will be able to cope with the strain of the operation and recovery process.