Did the Buddha ever mention the Upanishads or the Vedas?

I don't know a lot about those two, but I hear that they are full of wisdom. Since they date farther back than buddhism, I was wondering if the Buddha ever mentioned them. What did he think of them? If he didn't mention them as such, he probably mentioned some concepts that are contained in them; Apart from obvious concepts contained in those two that also are within Buddhist thought (E.g. Karma).