Authorities in Maine are investigating after a threatening letter was sent to a Portland mosque.
Portland police said the Islamic Society of Portland, a mosque and a community center, received a letter threatening the local Muslim community on Tuesday.
Investigators said they're working with postal officials and the state attorney general's office, and that the letter may have originated overseas.
In addition to working closely with members of the local Muslim community, Portland police said officers are providing additional patrol around mosques and other gathering places during Ramadan.
"We will continue to provide this support to the Muslim community in hopes of instilling a sense of security and to deter further threats," the department said in a statement. "This type of conduct is unacceptable and will not be tolerated in our community."
Anyone with information about the threatening letter is asked to call Portland police at 207-874-8575.