The speech stopped short of a flat-out endorsement of the agreement. But Mr. Khamenei did not include any specific criticism of the deal or its terms, and analysts said that would probably speed its acceptance by Iran’s Supreme National Security Council and Parliament.

At the same time, Mr. Khamenei made clear that a single agreement did not mean Iran’s overall relationship with the United States would change, and he promised to continue Iran’s support for allies in the region, including President Bashar al-Assad of Syria and the Lebanese-based Hezbollah movement. He praised Iran’s annual anti-Israel rally, known as Quds Day.

Under the nuclear agreement, Iran must give up large parts of its nuclear program, including two-thirds of its uranium-enrichment centrifuges, and it must accept intrusive inspections, even of military sites. Iran’s leaders say that what matters is Western acceptance that Iran will continue to have a nuclear program, and that when the agreement ends in 2025 Iran will be able to enrich uranium and plutonium without limits.

A draft resolution canceling sanctions against Iran and formalizing the steps that Iran is expected to take is to be presented at the United Nations Security Council on Monday. The five permanent members of the Council — Britain, China, France, Russia and the United States — negotiated the nuclear deal with Iran along with Germany.

Several leading members of Congress, both Democrats and Republicans, have urged President Obama not to submit the agreement to the Security Council until Congress has first voted its approval or disapproval.

Critics say that by restoring Iran’s potential access to around $100 billion in frozen funds around the world, the agreement will free the country to finance an expanded campaign of aggression in the Middle East. Iranian hard-liners have complained that it will reduce the nuclear program to just a symbol, not an industrial effort. Many hard-liners also fear that it will end Iran’s enmity toward America.

Mr. Khamenei nodded to the complaints, accusing the West of trying to “remove all of the nuts and bolts of Iran’s nuclear industry.” And he made clear that any notions that relations with the United States would now thaw and that the two countries could cooperate on other matters were “dreams” that will not become a reality.