Extra police were at Eden Prairie High School throughout Thursday's school day after rumors spread on social media about a student threatening to bring a gun to school.

Principal Conn McCartan said no incidents occurred, but two extra police officers were at the school Thursday in addition to the two regular school resource officers.

In a letter sent to Eden Prairie parents Thursday, McCartan reassured them that rumored threats were unsubstantiated. Besides extra police at the high school, McCartan added that school staff will be extremely vigilant.

The rumor of a student threatening to bring a gun to school surfaced Wednesday as the school was investigating tensions between some students about messages posted on Twitter. By the end of the school day Wednesday, McCartan said police officers determined that the rumor wasn't true, but it continued to spread overnight on social media.

"While we need to hear from students about what is happening at the high school, it is challenging when the situation gets inflamed when rumors are shared through social media among students and parents," he wrote, adding that "at this point, nothing of a threatening nature has been substantiated."

The high school doesn't have classes on Friday.

Kelly Smith • 612-673-4141 Twitter: @kellystrib