TEHRAN — Iran’s supreme leader on Wednesday ruled out allowing international inspectors to interview Iranian nuclear scientists as part of any potential deal on its nuclear program, and reiterated that the country would not allow the inspection of military sites.

In a graduation speech at the Imam Hussein Military University in Tehran, the supreme leader, Ayatollah Ali Khamenei, widely believed to have the final say on whether Iran accepts a deal if one is reached next month, denounced what he said were escalating demands by the United States and five other world powers as they accelerate the pace of the negotiations with Iran.

“They say new things in the negotiations,” Ayatollah Khamenei told the military graduates. “Regarding inspections, we have said that we will not let foreigners inspect any military center.”

Image Ayatollah Ali Khamenei, Iran's leader, in Tehran on Wednesday. Credit... Uncredited/Office of the Iranian Supreme Leader, via Associated Press

Like last summer, when he vowed that Iran would ultimately build an industrial-scale uranium enrichment capability — with 190,000 centrifuges, or 10 times the number now installed — the ayatollah’s comments are bound to cause deep complications for Iran’s negotiators, led by Foreign Minister Mohammad Javad Zarif.