(CNN) A pregnant woman woman who survived the New Mexico bus crash that killed eight people gave birth to twins hours afterward, hospital officials told CNN Friday.

The two children were born at Rehoboth McKinley Christian Health Care Services clinic in Gallup. They were then transferred to the neonatal intensive care unit at the University of New Mexico Hospital in Albuquerque, Sonlee West, a surgeon and director of the hospital's trauma unit, said Friday.

West said the children were in critical condition.

The mother's name and condition were not available. Authorities initially released the identity of only one person involved in the crash.

Bus driver Luis Alvarez, 49, of Santa Teresa, New Mexico, was among those killed.

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