KALISPELL, Mont. — Flathead County schools have canceled football games and other weekend extracurricular activities due to threats made earlier this week that the sheriff said could be credible.

Whitefish Superintendent Heather Davis Schmidt told the Flathead Beacon that schools have been advised by law enforcement to prevent “large groups of students from being together” amid this situation.

School administrators consulted with law enforcement officers and were told the situation has not been resolved before deciding to cancel classes on Friday along with weekend sporting competitions.

“Based upon our estimation, without revealing any details of the investigation, we certainly feel that there is a credible threat, or at least a potentially credible threat,” Sheriff Chuck Curry said.

Athletics directors said they would try and reschedule the games, if possible.

Officials have not released the contents of the threats, which were apparently sent by text and email, beginning Wednesday. Some threats were received Thursday morning, a day after a student at a high school southeast of Spokane, Washington, shot and killed one student and injured three others.

Columbia Falls and Kalispell police, the Flathead County sheriff’s office and the FBI are investigating. “Persons of interest” had been interviewed and the investigation made progress on Thursday, Curry said.

“We pretty much have every resource on this right now,” Curry said.

Classes were canceled Thursday and again on Friday. The closure impacts about 15,700 students in more than 30 public and private schools, including high schools in Bigfork, Columbia Falls, Kalispell and Whitefish along with Flathead Valley Community College campuses in Kalispell and Libby.

The weekend sports cancellations include volleyball matches involving the Kalispell and Helena high schools, Flathead High’s home football game against Missoula Sentinel, Glacier High’s football game at Helena High, Bigfork’s football game against Eureka, home football games for Whitefish and Columbia Falls and Whitefish High’s homecoming activities.

School officials have not yet decided if classes will resume on Monday.