"No agreement has been signed yet and this [recent] deal is only a communique in which they have yielded to Iran's enrichment right," Ayatollah Ahmad Khatami was quoted as saying by the official Islamic Republic News Agency.
Iran and Western countries brokered a nuclear agreement last month in Geneva, Switzerland, that requires Iran to roll back certain aspects of its nuclear program in exchange for relief from economic sanctions.
Iran has said it wants to enrich uranium to 20 percent purity, a level seen as a key step in the development of a nuclear weapon.
The interim deal calls on Iran to restrict its enrichment activity.
Khatami said Iranian leaders have put their trust in their nuclear negotiating team but were wary of Western intentions.
"That is because as the Koran has stated: They do not honor the treaties and pacts, and their god is their interests," he said.
Rep. Ed Royce, R-Calif., chairman of the House Foreign Affairs Committee, said Tuesday he summoned U.S. Secretary of State John Kerry to testify Dec. 10 about the agreement reached with Iran. Royce said the deal left room for Iran to continue working on a program he says is geared toward producing a nuclear weapon.
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