The US has had constructive talks about the Iran nuclear deal with Britain, France and Germany but is making contingency plans should they fail, Reuters reported quoting the lead U.S. negotiator.

U.S. President Donald Trump gave an ultimatum on Jan. 12 to the European powers, saying they must agree to “fix the terrible flaws” of the 2015 Iran nuclear deal or he would refuse to extend the U.S. sanctions relief on Iran that it calls for. U.S. sanctions will resume unless Trump again waives them on May 12.

“We have had constructive talks with the Europeans toward a supplemental agreement but I can’t predict whether we will reach an agreement with them or not,” Brian Hook, the State Department policy planning director, told reporters in a conference call.

“We are engaged in contingency planning because it would not be responsible not to,” said Hook, the lead U.S. negotiator in the talks with the Europeans. “We are kind of dual tracking this.”