Menstruating migrants girls being held at detention centers near the U.S.-Mexico border are 'visibly' bleeding through their pants and are forced to wear their soiled clothes, according to a new lawsuit.

On Monday, 19 states being led by California, filed a lawsuit against the Trump administration and the Department of Homeland Security's standards for detaining migrant children.

The 26-page investigation outlines what Washington State Attorney General Bob Ferguson calls 'appalling conditions'.

The lawsuit interviewed a number of detained migrant children who described their time at the detention centers as, among other things, 'uncertain'.

On Monday, a lawsuit was filed against the Trump administration's regulations regarding living conditions in detention centers

Lawsuit: 'Although the guards knew they had their periods, they were not offered showers or a change of clothes, even when the other girl visibly bled through her pants'

'The children described their time in CBP facilities as filled with uncertainty, since most of them were not told how long they would be kept in detention or what would happen to them next.'

One girl describes to investigators she went as long as 10 days without being offered a shower, even when she was on her period.

She was reportedly only given one sanitary pad a day.

The investigation tells of another young girl who bled through her pants, but was not given a change of clothes and forced to wear her dirty garments.

'Although the guards knew they had their periods, they were not offered showers or a change of clothes, even when the other girl visibly bled through her pants. This girl had no choice but to continue to wear her soiled underwear and pants.'

Detained children describe not getting proper sleep because 'there was not enough room for everyone to lie down at the same time'

Immigrant children in detention centers have little access to basic sanitary needs, including toilet paper, tooth paste, soap, showers and private bathrooms

The children describe the facilities as 'freezing' and only being given 'aluminum' blankets for warmth.

Children who came in with extra clothes had their items confiscated by immigration officers who refused to return the clothes even if children asked.

Detention centers are reportedly so crowded that children are not able to get adequate sleep because 'there was not enough room for everyone to lie down at the same time'.

The investigation also reveals that children in detention centers do not have consistent access to soap, toothpaste, tooth brushes, toilet paper, private bathrooms and other basic sanitary needs.

The lawsuit, filed by 19 states and is spearheaded by California, assert the Trump administration is in violation of the Flores settlement

Bob Ferguson said in his press release that the 'prison-like conditions will have profound, long-term impacts on their mental and physical health'.

The lawsuit is directly challenging the Trump Administration's new regulations allowing ICE to reverse the 'Flores settlement'.

The Flores settlement limits the amount of time the government can detain immigrant children, advising 20 days or less. It also has minimum guidelines on sanitation and living conditions.

The Trump administration's reworking of this rule, set to go into affect in about two months, would allow detention centers to hold migrant families indefinitely after transferring them from border custody.

Ferguson's press release said: 'The Trump Administration’s new rules unlawfully permit federal officials to detain children and families in unlicensed facilities without adequate standards of care to protect the safety and well-being of immigrant children.

The investigation was conducted by an Investigation Supervisor in the Civil Rights Division.