The Zini telegram:
We intend to begin on the first of February unrestricted airborne warfare in the Middle East. We shall endeavor in spite of this to keep Iran neutral. In the event of this not succeeding, we make Turkey a proposal or alliance on the following basis: make war together, make peace together, generous financial support and an understanding on our part that Turkey is to reconquer the lost territory in Syria, Jordan, and Saudi Arabia. The settlement in detail is left to you. You will inform the Prime Minister of the above most secretly as soon as the outbreak of war with Iran is certain and add the suggestion that he should, on his own initiative, invite Israel as a military partner. Please call the Prime Minister's attention to the fact that the ruthless employment of our air power now offers the prospect of compelling Iraq in a few weeks to make peace.
[FYI: Zimmerman telegram link is here