This movie is in color and in American English. It is probably from around the mid 60’s, but that is a guess. It takes place during WWII.
The plot of this movie is that an elite group of allied soldiers–probably English and American, although one of the Americans speaks German fluently–are assembled to sneak into Nazi territory and blow up a dam. There are probably about half a dozen soldiers, who are probably all white, but one might be a black man. They are somewhat aided (when in Nazi territory) by a very tough, beautiful white woman with dark hair who carries a really long rifle.
The Nazis are building some powerful, secret weapon in a cave (or mine? someplace underground-ish) that has a lab with shiny equipment and scientists who are mostly begrudgingly cooperating with the Nazis. They are not all “loyal” Nazis, but the Nazis have taken their families to “keep them safe” so they feel compelled to help create the weapon. Some of the scientists might even be Jewish people who are being forced to cooperate as well.
The idea is that the allied soldiers will blow up a certain dam, which will cause the valley with the cavelab in it to flood, thus destroying the secret weapon and all the Nazis and scientists involved. The woman who is helping them wants to try to warn some of the scientists so they can try to get away before the valley floods. Technically the soldiers’ orders do not allow for such a warning, but some of them have moral qualms about the situation with the scientists who aren’t really Nazis, so there is strife within the group.
I don’t know how this movie ends, but my guess is the Nazis lose.
This movie was probably released in the theaters, but was shown on TV (in America) once or twice in the mid to late 70s. I don’t know who any of the actors are. All I can say is that the woman looks a bit like Sophia Loren, but is definitely not Sophia Loren.
Thank you for any help you can give. I welcome all suggestions.