The interim U.S.-Iran peace accord allows United Nations nuclear inspectors to access Iran, the head of the International Atomic Energy Agency (IAEA) said on Friday, despite Tehran’s previous indication that key facilities would remain off-limits.

IAEA Director General Rafael Grossi said inspections were required under the agreement reached between the two sides and that the agency needed access to verify Iran’s nuclear activities.

“There is an agreement and to comply with that agreement, the IAEA will have to have access and inspect,” Grossi told reporters in Japan. “We hope to be there soon.”

The United States and Iran signed a memorandum of understanding last week that opened the way for 60 days of negotiations aimed at resolving outstanding issues, including disputes over Iran’s nuclear program.

However, Iran’s deputy foreign minister Kazem Gharibabadi said on Wednesday that there were no plans to allow inspectors access to key sites before a final agreement with Washington was reached and sanctions were lifted.

Grossi said IAEA officials had already held an initial exchange with Iranian authorities over technical issues. He added that the first priority of any inspection visit would be checking whether seals placed on previously monitored nuclear material remained intact and whether any material was missing.

“Intentions are not enough. We have to have a very strong verification system in place,” Grossi said.

The IAEA chief also said Iran had not informed the agency how much of its enriched uranium remained after U.S. and Israeli attacks or where the material was located.

Before the conflict began, the IAEA estimated that Iran had 440.9 kilograms of uranium enriched up to 60%. According to the agency’s assessment, further enrichment of that stockpile could provide enough material for 10 nuclear weapons.