HOUSTON - A suspicious envelope with a white powdery substance was mailed to an elementary school in the US city of Houston on Friday, a local TV station reported.

The envelope was delivered to Franklin Elementary School in Houston, Texas, and arrived at the school at noon, according to local TV channel KPRC.

Houston Fire Department officials who went to the scene did not find anything alarming about the envelope after initial testing, the report said.

However, the report said, the area where the envelope was received was quarantined until the all-clear was given.

A letter was sent by the school's principal to parents to alert them of the incident.

"A letter containing a white powdery substance arrived on campus through the U.S. mail. Testing on the envelope and the powdery substance revealed that the substance DID NOT pose a threat to our students or staff," the letter reads.

Additional tests will be done on the substance in the envelope, school authorities said.