Counter terrorism police launch probe into bomb threat sent to American mosque from Sheffield
The bomb threat, made against the Masjid Bilal mosque in Lexington, Kentucky, was received in the post from Sheffield on Saturday.
The Council on American-Islamic Relations (CAIR) said that the letter contained a green index card wrapped in a blank sheet of paper.
Counter terrorism police said they are aware of the "malicious communication which have been received the United States of Amera" and have launched an investigation to identify the origin.
A spokesperson said: "We are looking into the possibility that the communication is linked to a number of suspicious packages and malicious communications reported at locations in London, South Yorkshire and America."
Police in America have advised staff at the mosque to increase its security following the incident.