GRANBURY, Texas (CBSDFW.COM) – Two Granbury High School seniors died Monday while swimming in the Wheeler Branch Reservoir near Glen Rose, Hood County authorities said.

Both victims were flown by air ambulance to an area hospital according to Somervell County Fire Chief Mark Crawford, but neither survived.

Granbury ISD released a statement on its Facebook page saying it’s mourning the loss of two students who died Monday in an incident that was not school-related.

Counselors are on campus for students and administrators.

Here is the complete statement:

Granbury High School is mourning the loss of two students who tragically passed away on Monday. This was not school-related. GHS counselors and administrators as well as local ministers are available for students needing to discuss this during an open time at the GHS auditorium, which will be open though early evening tonight. The counselors are prepared to assist students and staff members on Tuesday morning as well. The identity of the students will be released upon consent of family members.

The students identities have not yet been made public by authorities.

The Hood County Sheriff confirmed it was “senior skip day.”

“We don’t sanction a senior skip day,” said Granbury High principal, Jeremy Ross.  “That’s not something that’s ours. We don’t own that. That’s something the kids are going to do and the parents are going to allow.”

Friends of the students who died say the boys, less than a month from graduating high school,  were at a lake when one of them started having trouble in the water and the second student jumped in to try and help him.

Some 50 to 60 students showed up at Granbury High School Monday evening to speak to grief counselors in the hours after losing two classmates.