A transgender migrant has died after becoming sick while in Immigration and Customs Enforcement (Ice) custody, sparking renewed claims of medical neglect and human rights violations.

Johana Medina León, a 25-year-old asylum seeker from El Salvador, died on Saturday at a hospital in El Paso, Texas, after she was detained for over a month and complained of chest pains, officials said. Leon had repeatedly pleaded for medical help and was held in poor conditions, advocates who had contact with her and others at the privately run New Mexico detention center said.

Leon’s death echoes the case of Roxsana Hernández, a trans Honduran woman who had HIV and died in Ice custody one year ago. Hernández died due to dehydration and complications related to HIV, according to her family’s attorneys. The tragedy sparked international outrage about the US government’s treatment of trans migrants fleeing violence and seeking asylum.

“It’s painful and gut-wrenching,” said Isa Noyola, deputy director of the immigrant rights group Mijente, who has visited the Otero county processing center where Medina León was detained. “Ice is wreaking havoc inside our detention centers … They are in the business of making people unhealthy and violating human rights.”

Immigration officials first encountered Medina León on 11 April at the Paso del Norte port of entry, by El Paso, Texas and Ciudad Juárez, Mexico. She was transferred to Ice custody, and she passed her first interview in the asylum process a month later, with authorities determining she had “credible fear” of persecution if forced to return to El Salvador, Ice said in a statement on Monday.

Medina León, who advocates said was also known as Joa, was transported to a medical center on 28 May from the processing center where she was being held, complaining of chest pains, and was released on parole, according to Ice. She died four days later, though officials have not released a cause of death. Medina León had requested to be tested for HIV and tested positive, according to Ice’s statement.

The Otero processing center, run by a private firm called Management and Training Corporation (MTC), has been the subject of a range of civil rights complaints over the years. The American Civil Liberties Union (ACLU) has accused the center of lacking adequate medical and mental healthcare, and alleged that trans and queer detainees suffer from harassment, abuse, discrimination and retaliation.

Last year, the ACLU also filed a lawsuit against the Trump administration’s “arbitrary detention” of asylum seekers, targeting the Otero center on behalf of plaintiffs who had fled Mexico to escape cartel violence.

Nathan Craig, a volunteer with a group called Advocate Visitors with Immigrants in Detention (Avid) in the Chihuahuan desert, has visited trans detainees at Otero, and told the Guardian he was aware of three other trans women currently at the facility. Although he never met Medina León, he said other women reported that she appeared to be getting sicker and appeared to be losing weight during her detention. The women all experienced bouts of illnesses and colds, he added.

“These are individuals who are fleeing persecution for being transgender. They’ve already suffered some significant issues,” he said. “They are fragile. They are vulnerable.”

Craig said some of the women had suffered mental health consequences due to discrimination, harassment and isolation.

Some of the women are segregated and isolated under the guise of protecting them, added Margaret Brown Vega, another Avid volunteer. “Solitary is used in an abusive way,” Vega said.

Although LGBT people in immigration detention made up 0.1% of the population in 2017, they accounted for 12% of victims of sexual assaults reported in Ice custody, according to government data. Trans women are regularly detained at all-male facilities, and Ice reported to Congress last year that nearly 40 trans people were placed in solitary confinement in 2017 – 14 of them involuntarily, and 25 who requested it because being in general population was so unsafe.

“It’s clear that they are not fit to meet the needs of trans and queer immigrants,” said Emilio Vicente, communications manager with Familia: Trans Queer Liberation Movement, about the detention facilities. His group had just coordinated a week of actions in honor of the one-year anniversary of Hernández’s death when news of Medina León’s death broke.

“These deaths are preventable,” he said, adding: “They were seeking asylum and instead they found death … Ice is not accepting any responsibility.”

Corey A Price, field office director for Ice enforcement and removal operations in El Paso, deflected blame for Medina León’s death in a statement, saying: “This is yet another unfortunate example of an alien who enters the United States with an untreated, unscreened medical condition.” Ice further claimed that it provided “comprehensive medical care”, including a “full health assessment within 14 days” of entering custody.

Activists said they were working to get in touch with Medina León’s family, and it was unclear if she had an attorney.

Her death comes as the White House has dramatically escalated its attacks on trans rights, including new discriminatory policies in housing and healthcare, and the continuing military ban.

“It’s like reliving your nightmare over and over, and you can never get out of it,” said Noyola, recounting the phone call she had received over the weekend about Medina Leon’s death. “We have been in survival mode for so long with the daily transphobic attacks … But the community is not backing down.”