(CNN) -- Two days of talks with Iran have failed to produce agreement on how to verify that Iran's nuclear program remains peaceful, the International Atomic Energy Agency announced Tuesday.
Iran also refused to allow a team from the U.N. nuclear watchdog agency to visit its military base at Parchin, southeast of Tehran, during the two-day visit, the IAEA said.
Iran could send U.S. gas prices to $5 a gallon.
Iran says it is producing enriched uranium to fuel civilian power plants and has refused international demands to halt its production. But the IAEA reported in November that it had information to suggest Iran had carried out some weapons-related research.
In the meantime, Israel is making clear it is pondering an attack on Iran's nuclear infrastructure. Israel is widely believed to have nuclear weapons itself, though it has never declared itself a nuclear power and considers Iran an existential threat.
Iran has threatened to cut off the Strait of Hormuz, the only shipping lane out of the oil-rich Persian Gulf, if it is attacked. But last week, it also proposed a resumption of long-stalled talks with European powers and Security Council permanent members aimed at resolving the issue.