“Despite my strong inclination, I have not yet withdrawn the United States from the Iran nuclear deal. Instead, I have outlined two possible paths forward: either fix the deal’s disastrous flaws, or the United States will withdraw,” Trump said in a statement.

He added:

I am waiving the application of certain nuclear sanctions, but only in order to secure our European allies’ agreement to fix the terrible flaws of the Iran nuclear deal. This is a last chance. In the absence of such an agreement, the United States will not again waive sanctions in order to stay in the Iran nuclear deal. And if at any time I judge that such an agreement is not within reach, I will withdraw from the deal immediately.

To drive the point home, Trump said, “No one should doubt my word. I said I would not certify the nuclear deal—and I did not. I will also follow through on this pledge.”

There's more: http://www.breitbart.com/national-security/2018/01/13/trump-warns-european-allies-fix-iran-nuclear-deals-disastrous-flaws-america-withdraws/