Let me also take this opportunity to apologize to all the spades I ever may have called a 'spade'.
In any event I regret these words were used.
'These words' weren't used. YOU used them. One could say that they regret someone else's words with I regret these words were used, but what Kissinger should have said, if he was actually apologizing for what he said, was, "I regret using these words." as opposed to putting it off on some unspecified passive voice.