Eight members of the US House of Representatives have written of their concerns about the treatment of Christians in the UK and "existential threats" to their freedoms, "even freedom of thought."
The letter was led by Representative Chip Roy and sent to Rashad Hussain, the US ambassador-at-large for international religious freedom.
It says that the UK is "on an unsettling path" with the spread of buffer zones around abortion clinics across the country.
These buffer zones are imposed by 'Public Spaces Protection Orders' enacted by local city councils, and criminalise peaceful pro-life activity in the areas surrounding abortion clinics.
Banned activities include prayer and offers of support and information to women about alternatives to abortion. They also ban any perceived disapproval of abortion.
Recently, two pro-life volunteers, Isabel Vaughan-Spruce and Catholic priest, Fr Sean Gough, were charged with intimidating users of a closed abortion clinic after praying silently inside a buffer zone parameter. They were both cleared of all charges by a UK court in February.
The letter from Roy and the other Representatives called their arrests a "gross" and "aggressive" assault on individual freedoms.
"The UK is now on an unsettling path that could potentially result in existential threats to freedom of speech, freedom of religion, and even freedom of thought," they said.
They express concerns that legislation is being considered to make buffer zones nationwide.
"Even more disturbing, Parliament is considering legislation that would implement these antireligious-freedom censorship zones around abortion facilities across all of England and Wales, and recently rejected amendments to this legislation that would have clarified that silent prayer and consensual conversations cannot be construed as crimes," they said.
"Arresting individuals for silent prayer is a gross, aggressive, and needlessly escalatory assault on one's fundamental freedoms."