German Foreign Minister Sigmar Gabriel said Sunday that he feared US President Donald Trump would quit the Iran nuclear deal next week. Trump is a stern critic of the 2015 accord, which he has called "the worst deal ever", and US officials say he intends to tell US Congress next week that Tehran is not honouring its side of the bargain. "The United States is likely to quit the Iran agreement next week - that is my great concern," Gabriel was quoted as saying by national news agency DPA.