STEUBEN, Mich. (AP) — A Wisconsin-based fighter pilot died after a plane crashed in the Hiawatha National Forest in Delta County during a training mission, military officials said Thursday.

The Wisconsin Air National Guard’s 115th Fighter Wing announced the pilot’s death Thursday, but said the pilot’s identity will not be released until 24 hours after family members are notified.

The cause of Tuesday night’s crash wasn’t immediately known and is being investigated, officials said.

“We are deeply saddened by this tragic loss, and our thoughts and prayers are with the family during this difficult time,” 115th Fighter Wing Commander Col. Bart Van Roo said. “Today is a day for mourning, and the 115th Fighter Wing along with the entire Wisconsin National Guard stands with the pilot’s family as we grieve the loss of a great Airman, and patriot.”

The 115th Fighter Wing participated in a coordinated search effort with local emergency responders, the U.S. Coast Guard and other government agencies.

The 115th Fighter Wing plans to provide more details on Friday.