PARIS — The International Atomic Energy Agency said on Monday that Iran had agreed to resolve all outstanding issues with the agency and would allow international inspectors “managed access” to two important nuclear facilities that have not been regularly viewed.

But the promise of wider scrutiny did not extend to one of the most contentious locations: the Parchin military site southwest of Tehran. Inspectors from the agency, the United Nations’ nuclear watchdog, have been trying for months to see selected areas of that site, where they suspect that Iran at one time tested triggering devices for nuclear weapons.

“This is an important step forward to start with, but much more needs to be done,” Yukiya Amano, the director general of the agency, told reporters in Tehran.

The agreement came on the heels of talks between Iran and six world powers over Iran’s nuclear program. Those talks ended without an agreement that would have eased economic sanctions in exchange for verifiable assurances that Iran would not pursue the construction of a nuclear weapon. Western diplomats said Iranian negotiators balked at a proposed agreement and did not give enough concrete assurances of the country’s peaceful intentions.