A four-year-old boy became the second migrant minor to reportedly die from respiratory failure within a span of two days after crossing the United States-Mexico border.

Axar.az reports the child, whose name has not been released, was part of a group of a dozen migrants who turned themselves in to a U.S. Border Patrol supervisory agent with the Rio Grande Valley Sector along a remote area near La Joya, Texas on November 21, U.S. Customs and Border Protection said in a statement released Saturday.

A preliminary autopsy indicated his death was caused by pneumonia and acute respiratory failure.

According to CBP data, there were 557 deaths at the southwestern border during the fiscal year 2021, which spanned from October 1, 2020, to September 30, 2021.