United Nations High Commissioner for Human Rights Michelle Bachelet said Monday she is “appalled by the conditions” being forced upon migrants after crossing the southern U.S. border and admonished the federal government for failing to find noncustodial alternatives.

“Any deprivation of liberty of adult migrants and refugees should be a measure of last resort,” she said, adding that where detention is necessary, it should be for the shortest period and under conditions that satisfy international human rights standards.

“Clearly, border management measures must comply with the State’s human rights obligations and should not be based on narrow policies aimed only at detecting, detaining and expeditiously deporting irregular migrants,” Bachelet said.

The high commissioner singled out the treatment of migrant children, saying she was “deeply shocked that children are forced to sleep on the floor in overcrowded facilities, without access to adequate healthcare or food, and with poor sanitation conditions.”

In 2018, Bachelet’s predecessor as high commissioner criticized the Trump administration’s child-separation policy. “The thought that any state would seek to deter parents by inflicting such abuse on children is unconscionable,” Zeid Ra’ad al-Hussein said at the time.

On Monday, Bachelet said immigration detention — which is never in the best interests of a child — can have a significant impact on a child’s health and development. “[C]onsider the damage being done every day by allowing this alarming situation to continue,” she said.

Several human rights bodies have determined that detention of migrant children under current conditions at the U.S. border violates international law as “cruel, inhuman or degrading treatment.”

Bachelet’s statement comes days after the Department of Homeland Security’s internal watchdog issued a report about border processing center conditions.

The Office of Inspector General concluded the “urgent” situation required “immediate attention and action” and advised the federal government to “take immediate steps to alleviate dangerous overcrowding and prolonged detention of children and adults.”

According to the Associated Press, Tuesday’s report stated that at least three facilities denied children access to showers and “some children under age 7 had been held in jammed centers for more than two weeks. Some cells were so cramped that adults were forced to stand for days on end.”

Notwithstanding the report, DHS officials have remained steadfast in their defense of Border Patrol station conditions. On Sunday, acting Homeland Security Secretary Kevin McAleenan called the situation “extraordinarily challenging” during an interview on ABC’s “This Week.”