BOSTON — Doctors and other staffers at Boston Children’s Hospital are being threatened with violence over its surgical program for transgender youths, administrators said, and other U.S. children’s hospitals are also being harassed online.

Boston Children’s is home to the first pediatric and adolescent transgender health program in the United States. It became the focus of far-right social media accounts, news outlets and bloggers last week after they found informational YouTube videos published by the hospital weeks ago about surgical offerings for transgender patients.

The hospital swiftly removed the videos. It said in a statement Tuesday that it is working with law enforcement to protect its staff and patients and to “hold the offenders accountable,” adding that it rejects the “false narrative” spreading online.

Some of the same social media accounts are now shifting their attention – and that of their millions of followers – to similar gender care programs at children’s hospitals in Pittsburgh and Phoenix. Those hospitals did not immediately respond to email and phone messages seeking comment.

Transition treatment is under attack in many states, with some labeling it a form of child abuse or barring Medicaid coverage. Critics argue that safety should be well established before subjecting youths to potentially irreversible treatments.

>But many medical groups support allowing varying types of medical treatment for transgender youths, citing evidence that it can improve their well-being, although rigorous long-term research on benefits and risks is lacking.

Republican candidates have also been disparaging transgender people in midterm election campaigns in a strategy designed to motivate the conservative base and sway swing voters, political observers say.

C.P. Hoffman, senior policy counsel at the National Center for Transgender Equality, said this is the first time they’ve heard of intense, targeted online attacks on children’s hospitals, though other organizations that provide services to trans people have faced significant harassment.

“It really makes one worry about the safety of trans youth and their families and the individuals who provide services to them,” they said.

The Massachusetts Transgender Political Coalition also condemned the attacks as baseless claims continuing an assault on trans youth and trans health care that is spreading across the U.S.

“Attacking children and those who care for them for seeking appropriate medical care is an indefensible position and at its core, an ill-fated attempt to erase transgender people from public life,” the coalition said in a statement.

The critics cited the videos and snippets of previous language on the hospital’s website to claim that Boston Children’s Hospital was improperly performing gender-affirming surgeries, such as hysterectomies, on minors and “young” children. The response was swift and relentless, with a barrage of users demanding the hospital be shut down and calling the surgeries “mutilation,” “barbarism” and “child abuse,” while accusing its doctors of engaging in malpractice or illegal activity.

The hospital said it has received “a large volume” of hostile online messages, phone calls and harassing emails, including the threats of violence.

“We are deeply concerned by these attacks on our clinicians and staff fueled by misinformation and a lack of understanding and respect for our transgender community,” the hospital said in its statement.

The hospital has updated language across its websites to emphasize that to qualify for most gender-affirming surgical procedures, patients must be at least 18 and meet certain criteria, including undergoing intensive medical and mental health evaluations and submitting letters of support.

Some of the online critics pointed to information that once appeared on the hospital’s website that said to qualify for vaginoplasty at Boston Children’s, one must be at least 17 and meet certain criteria, as well as language for chest reconstruction and breast augmentation that remains on the website that says patients must be at least 15 and meet certain criteria.

Vaginoplasty is the creation of a vagina from existing genital tissue. A gender-affirming hysterectomy is the removal of the uterus and fallopian tubes, which can precede a phalloplasty, the surgical creation of a penis.

The hospital said it does not perform genital surgeries as part of gender-affirming care on a patient under age 18. It said that for surgical consultation, a patient must be 17 years old and 18 to 35 years old at the time of surgery.

The World Professional Association for Transgender Health, a global group that sets standards for medical care of trans youths and adults, recently lowered its recommended minimum age for starting gender transition treatment, including sex hormones and surgeries.

The new standards support starting hormones at age 14, two years earlier than before, and some surgeries at age 15 or 17, a year or so earlier than previous guidance. The group acknowledged potential risks but said it is unethical and harmful to withhold early treatment.

The Endocrine Society generally recommends starting those treatments a year or two later but is also updating its guidance. The American Academy of Pediatrics, the American Medical Association and the American Psychiatric Association are among other groups that support allowing medical treatment for transgender youths but don’t offer age-specific guidance.