DETROIT (AP) — A rabbi who packs a gun. A church installing security cameras. A police car protecting a mosque.

Houses of worship have traditionally been places of refuge where strangers are welcome. But high-profile attacks in recent years on an African-American church in Charleston, South Carolina, a synagogue in Pittsburgh and now mosques in New Zealand have made many worshippers and their prayer leaders rethink how protected sanctuaries really are.

"People are fearful for their lives, for their houses of worship, for the sanctuary of this mosque and other places of worship like the synagog...