I saw a movie that I'm sure is available on DVD but don't remember the title. It is basically a thriller or horror theme where a group of students are trapped in the school (I think it may have been a private school) and can't get out because the school is being besieged by some enemy.
Anyone have suggestions as to the identity of this film?

The plot described in this very condensed way can be related to many movies. First one that I remembered was Strandvaskaren (I think that Americans made a remake as they usually do with everything they see), but we should be given a few more information (at least country or language, or male/female/mixes school etc).

Me again-- more about the movie as I remember it. It is not Strandvaskaren (I looked into this one). It was an American made movie, and students were boys and girls both. in the story, one of the older boys was trying to lead a group of the students to a way of escape.

That sounds like Toy Soldiers but it's a boys school. I don't remember any girls.

https://www.imdb.com/title/tt3877296/?ref_=nv_sr_srsg_0
"The Cokeville Miracle" has children held hostage in a packed classroom by a pair of bombers. This is based on a true story. The incident took place at Cokeville, Wyoming USA

Fortress (1985)
https://www.rarefilmfinder.com/movie.php?id=199
The kidnapping starts in a school (a 1-room schoolhouse) then moves to a cave and on from there.

Oh you must be talking about the Australian movie "Fortress" (`1985). That is exactly what happened there.

Allein gegen die Zeit (TV Series) with Ruby O. Fee. She's got an entry here.