10:46 a.m.
School officials say say all high school students will be dismissed at 11 a.m. as a result of an ongoing investigation.
Police stress there is not an immediate threat at the time.
9:31 a.m.
Police officials are stressing there is not a threat at this time. They are asking parents not to come up to the school, as it will create unnecessary confusion on campus.
Parents are also asked to refrain from calling the school and the police department, leaving the lines free for emergency calls.
9:21 a.m.
Plymouth-Canton High School is on a soft lockdown as police assess a threat situation.
Canton Township Police are at the school. Classes will continue.
This story will be updated with more information as it comes in.
