Iran test-fired a new generation of surface-to-surface ballistic missiles on Sunday, its state news agency reported, a move that could complicate the implementation of the country’s July nuclear deal even as its parliament ratified the historic pact’s outlines.

Iran tested a long-range missile called the Emad, which Defense Minister Hossein Dehghan said was capable of precise control, according to a report from the Islamic Republic News Agency.

“We...