HOUSTON (AP) - Authorities say a 6-month-old migrant girl who was hospitalized after being taken across the U.S.-Mexico border illegally has improved to stable condition.

The baby was airlifted Saturday to a hospital in Corpus Christi, Texas, and listed in critical condition. U.S. Customs and Border Protection said Thursday that the infant had been upgraded and transferred to a hospital in Houston.

CBP says the child was placed in the custody of the U.S. Department of Health and Human Services, which typically holds children unaccompanied by a parent.

The baby's father was sent to U.S. Immigration and Customs Enforcement. CBP says he has a "criminal history," one of the grounds border authorities can still use to separate a parent and child. CBP did not specify the father's past convictions

Six children have died in the last year after being detained by the Border Patrol.

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