London - Protesters who want critically ill British baby Charlie Gard to receive an experimental medical treatment are planning a rally and prayer vigil on Sunday, while hospital officials say emotions are running so high in the heart-breaking case they have received death threats.Activists supporting Gard's parents will gather on Sunday afternoon outside the High Court in London where legal proceedings will resume on Monday with new medical evidence expected.Charlie has a rare genetic condition and suffers from brain damage.His parents are fighting to get him more medical care but Great Ormond Street Hospital officials say the experimental treatment won't work and will just cause the 11-month-old more suffering. They argue that his life support should be turned off and he should receive palliative care.Hospital chair Mary MacLeod said the London police have been contacted because of numerous threats received by the hospital's employees in the case."Staff have received abuse both in the street and online," she said. "Thousands of abusive messages have been sent to doctors and nurses whose life's work is to care for sick children. Many of these messages are menacing, including death threats."MacLeod said families visiting other ill children have also been "harassed and discomforted" on the grounds of the renowned hospital in London.Charlie's parents have lost all previous court cases, including one before the European Court of Human Rights, which were designed to force the hospital to let them bring their son to the United States for an experimental treatment.The loss in the European court, following an earlier defeat in Britain's Supreme Court, seemed final. But both Pope Francis and US President Donald Trump expressed an interest in Charlie's fate, and the hospital asked for a new court hearing because of what the family claimed was new medical evidence.Charlie has been examined by a US doctor who has treated similar cases. The doctor's testimony is expected to figure heavily in Monday's court proceedings, as are the results of Charlie's recent brain scans.