After months of escalating hostile rhetoric about the 2015 Joint Comprehensive Plan of Action (JCPOA), US Secretary of State Rex Tillerson is set to sit down next week for his first face-to-face encounter with Mohammad Javad Zarif, his Iranian counterpart. The two sides will meet in New York Sept. 20 at a ministerial-level meeting of the Joint Commission, the body established by the nuclear deal to resolve disputes among its signatories.

The Trump administration’s hawkish tack has predictably prompted a defiant Iranian response, albeit limited by President Hassan Rouhani’s pledge that Iran won’t be the first to violate the deal. But beyond the general irritation Iran has with the US rhetoric, Tillerson in particular has ruffled feathers in Tehran.

In June, Tillerson provoked outrage when he indicated to the House Foreign Affairs Committee that the United States has reverted to a policy of regime change, saying, “Our policy toward Iran is … to work toward support of those elements inside of Iran that would lead to a peaceful transition of that government.” More recently, on Sept. 14, Tillerson told reporters that Iran is “clearly in default” of “expectations” of the nuclear deal.

Yet Tillerson has publicly stated that he has “differences of views on things like [the] JCPOA” with President Donald Trump, while also asserting back in May that “in all likelihood,” he and Zarif “will talk at the right time.”