Poker players distinguish between a bluff (deception by way of playing) and the oral bluff (deception by way of an oral remark).
Bluff: Your negotiation partner created a deception by his way of playing. He pretended to have an alternate supplier or another offer. Let us say he met with your competitor during a trade show and made sure that photographs of this meeting circulated in your industry. You got the impression that he has reached an agreement with the competitor and that your only way of getting the contract is coming down with your price. This deception by way of playing is a legitimate means of negotiating. If you recognize the bluff, then please do not address it. It was not your opponent who made the mistake, it was you.
Oral bluff – lie: A lie is inacceptable! Your negotiation partner is not allowed to lie, and neither are you, of course. If you realize that your opponent is lying, please do not address it. What could you gain from it? Do not talk about the lie, but express your concerns. Do not focus on your opponent (you lied to me) but on the negotiation situation (in other cases, there had been some misunderstandings on these topics).