Scripture is clear about this in a bunch of different places. Psalms 95:5 and 1 Corinthians 10:20, for example.
You don't hear this from a lot of priests, though. Mine said it, though, and with specificity. He is from India. At Mass, he was very frank about it. "The gods the Hindus believe they are worshiping are actually evil spirits."
I couldn't believe he actually said something like that, but I applaud him for having the courage to say so, rather than being worried about what someone might say.