The UN's high commissioner for human rights has said she is "appalled" by the conditions that migrants face at US border facilities.

Her comments intensify the challenge to President Donald Trump over his administration's immigration policies.

Michelle Bachelet said children stopped by border agents should never have to be held in detention facilities, or be separated from their families.

Image: Conditions in camps have been described as 'appalling' by the UN's human rights head

She also added that detention should not be the norm for adults either, saying: "Any deprivation of liberty of adult migrants and refugees should be a measure of last resort."

In a statement, Ms Bachelet said many migrants and refugees set off on "perilous journeys with their children in search of protection and dignity and away from violence and hunger".


"When they finally believe they have arrived in safety, they may find themselves separated from their loved ones and locked in undignified conditions," she said.

"This should never happen anywhere."

The findings come after President Trump said at the weekend that migrants were "very happy with what's going on because, relatively speaking, they're in much better shape right now."

He also praised the work of border patrol agents on the Mexico-US border saying: "It's incredible what they're doing. They've had to become nurses. They've had to become janitors."

Image: A view of a centre in Clint, Texas, which has come under scrutiny in the past

Ms Bachelet, a former president of Chile, added: "As a paediatrician, but also as a mother and a former head of state, I am 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.

"Detaining a child even for short periods under good conditions can have a serious impact on their health and development - consider the damage being done every day by allowing this alarming situation to continue."

Image: The centres house migrants who have tried entering the US illegally

She said although she does recognise the rights of country's to set their own laws under which immigrants are allowed to enter the country, migrants human rights should still be recognised.

House speaker Nancy Pelosi said on Monday evening that more bills needed to go through the Senate to improve what she called "abhorrent" conditions at the south border.

She added that there were bills being considered that would stop separation of families, and impose specific types of care of children being held in the care of border agencies.

A report last week by the Department of Homeland Security's Office of Inspector General called the centres a "ticking time bomb", and demanded urgent action "to alleviate dangerous overcrowding and prolonged detention of children and adults".