Need help Identifying name of 1960's? war movie based in the Mountains somewhere

I am desperate to help a friend identify this movie. As described to me, the plot is something vaguely like this: Either US troops or british commandos could not control something and are trapped for some reason in the mountains. The commandos are apparently not good climbers? The local resistance saves them and helps them with their mission. One distinction: The resistance fighters know the Mountains and are accomplished climbers. The resistance effectively communicates with each other across the mountains in a way that intimidates the Enemy using a strange chattering noise.
The movie may have Stewart Grainger in it?
I would appreciate any and all help.
Thanks and regards,
diowrite
You may email me directly.

The Secret Invasion would seem to fit the bill. It has Grainger; it's a war movie; it has partisans. I didn't watch the whole movie, but I couldn't find any scenes with the chattering. Maybe you or your friend can.

I'll put this movie on my list of ones to watch.

It sounds a little closer to Guns of Navarone, but there is no chattering in that.

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Thanks for all the help.
It is not The Secret Invasion.
I got to admit, this is a tough search because I am relying on an old memory.
Supposedly, my friend says that he watched it in the mid 1960's.
It was a war movie in the Mountains.
Maybe with Stewart Granger.
There are possibly Commandos in need of help.
Some Mountain Men or Resistance Fighters help the Commandos.
The Mountain Men or Resistance Fighters have a way of communicating by calling out in a way that scares the enemy.
My friend says that his father yelled at him because the method of communicating noise over the TV that the Mountain Fighters made was annoying him.
Hope someone can sort out the bits and pieces and identify the Movie.
Thanks and regards,
diowrite

Is it The Heroes of Telemark?

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Thank you mark F.,
However, it is not The Heroes of Telemark.
I am grateful for the suggestion and I watched the movie (Heroes of).

I have been asked to find a film that was watched on a TV in the mid 1960's.
Vague Plot description: Possibly had Gregory Peck, but probably not, in WW II film.
There are 4 or 5 American soldiers in trouble and trapped by the German Army in some hills. (Could be the Vichy area of France?) Then, some resistance fighters, possibly with berets, who know the hills/the area and are good at climbing, rescue the Americans. Apparently there is lots of jumping and climbing in the movie.
The "resistance/mountain men" communicate with each other across the hills with yells that echo, due to the mountains, so the enemy does not know where the resistance fighters are but the communication is effective. The person who wants the film name said that the noise was so annoying his father yelled at him to turn the TV down. The "resistance/mountain men" help the Americans negotiate the hills and get where they need to go or rescue someone.
Remember this description is based on an old memory/vague recollection.
Maybe something will jog someone's memory.
Please Obi-Wan...
Kind regards,
diowrite

Thank you mark F.,
However, it is not "The Heroes of Telemark."
I am grateful for the suggestion and I watched the movie (Heroes of).

I have been asked to find a film that was watched on a TV in the mid 1960's.
Vague Plot description: Possibly had Gregory Peck, but probably not, in WW II film.
There are 4 or 5 American soldiers in trouble and trapped by the German Army in some hills. (Could be the Vichy area of France?) Then, some resistance fighters, possibly with berets, who know the hills/the area and are good at climbing, rescue the Americans. Apparently there is lots of jumping and climbing in the movie.
The "resistance/mountain men" communicate with each other across the hills with yells that echo, due to the mountains, so the enemy does not know where the resistance fighters are but the communication is effective. The person who wants the film name said that the noise was so annoying his father yelled at him to turn the TV down. The "resistance/mountain men" help the Americans negotiate the hills and get where they need to go or rescue someone.
Remember this description is based on an old memory/vague recollection.
Maybe something will jog someone's memory.
Please Obi-Wan...
Kind regards,
diowrite

If it is Gregory Peck it sounds like The Guns of Navarone, but I don't remember the communication stuff.

Thank you Will.15,
It is not the Guns of Navarone, unfortunately.
I thought of that same movie and my friend said it was not the one.
I have seen thousands of films and I cannot figure this one out.
Regards,
diowrite

Stewart Granger... you sure it wasn't James Stewart in the 1960 film Mountain Road?

Not sure about the chattering noise for communication though...

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