Doctors described Otto Warmbier, the American student recently released from North Korea, as being in a state of "unresponsive wakefulness" Thursday.

Medical officials at the University of Cincinnati held a press conference at the request of the Warmbier family to provide an update on their son's condition. Doctors refused to discuss Warmbier's prognosis and future treatment, citing client confidentiality.

Warmbier arrived in Ohio in a coma at 10 p.m. Tuesday, where he w as transported him to a neuroscience care unit. Doctors ran diagnostic tests and said Warmbier's vital signs are stable and he showed no signs of internal infection or dysfunction.

However, doctors said Warmbier displayed "profound weakness of muscles in his legs," spontaneous eye opening and inconsistent responses to verbal commands. Magnetic imaging of brain showed extensive loss of brain tissue in "all areas of the brain."

Doctors said this type of deficiency is usually the result of cardiopulmonary arrest, which is when the heart stops beating for a period of time and can't deliver blood to the brain.

They added there was no verifiable information about how or when the arrest occurred, though they believed that it occurred within weeks of an April 2016 brain scan provided to them by the North Koreans.

Doctors said they were provided with few medical materials from the North Koreans regarding Warmbier's treatment. They received another brain scan, dated July 2016, as well as numerical values of blood tests.

Doctors said they did not see any obvious signs of injuries, traumatic brain injury or bone fractures. They added that there was no evidence of botulism, as previously claimed by the North Koreans.