More children are crossing the U.S.-Mexico border without their parents.

Border Patrol encountered nearly 3,800 children traveling without a parent or guardian on the southwest border in September, according to data published by U.S. Customs and Border Protection.

The number of unaccompanied children encountered by Border Patrol agents has increased steadily since April.

According to advocates for migrants, some parents are sending their children across the border alone because they've lost hope the United States government will process their asylum claims in a timely manner.

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