One of the former conjoined Egyptian twins was taken off a ventilator and was breathing on his own Sunday, a week after doctors successfully separated him from his brother.

Mohamed Ibrahim (search) was breathing on his own, and his brother Ahmed could come off the ventilator as soon as Monday, said Dr. James Thomas, chief of critical care services at Children's Medical Center Dallas (search).

"Once each twin is breathing on his own without respiratory distress, his condition may be upgraded from critical to guarded," Thomas said.

The twins continue to make small gains, including motion in their arms and legs and improved response to verbal cues from the family and medical team, the hospital said. They are in critical but stable condition in the pediatric intensive care unit.

"The neurosurgical and medical teams are very pleased with the twins' progress so far," Thomas said.

Thomas said Ahmed has not had any repeat of a seizure he suffered Friday night.

The twins, joined at the top of their heads when they were born in Egypt (search) on June 2, 2001, were separated Oct. 12 during a 34-hour operation.

The hospital said the boys continue to run a low-grade fever, but do not appear to have an infection.