The US government says a 16-year-old Guatemalan died on Monday at a border patrol station in south Texas, the fifth death of a migrant child since December.

US Customs and Border Protection said in a statement that the border patrol apprehended the teenager in south Texas’s Rio Grande valley on 13 May. The agency said the teenager was found unresponsive on Monday morning during a welfare check at the agency’s Weslaco, Texas, station. The teenager’s cause of death is unknown.

The agency did not say why the teenager had been detained for a week, but said he was “due for placement” in a facility for youth operated by the US Department of Health and Human Services (HHS).

Federal law requires the Department of Homeland Security (DHS) to send minors unaccompanied by a parent or legal guardian to HHS within 72 hours of determining that the child is unaccompanied.

The border patrol has faced months of scrutiny over its care of children it apprehends at the border. A two-year-old child died last week after he and his mother were detained by the border patrol. On 30 April, a 16-year-old Guatemalan boy died after officials at an HHS detention facility noticed that he was sick. He was hospitalized in intensive care for several days before his death.

After the deaths of two children aged seven and eight in December, DHS ordered medical checks of all children in its custody and expanded medical screenings.

Trump administration officials have said they have passed a “breaking point” in the immigration detention system, with the numbers of parents and children crossing the border dramatically exceeding the capacity at facilities.

That strain is particularly acute in the Rio Grande valley, which has more unauthorized border crossings than any other region.

The border patrol has released photos of adults and children lying in small, military-style tents or on the grass and pavement outside of two of its stations. It also recently opened a 500-person tent near one port of entry and announced plans to open another.