Iran’s top leader casts doubt on efforts to revive a nuclear deal.

Iran’s top leader injected new doubts Wednesday into the stalled effort to save the country’s 2015 nuclear pact with major powers, accusing the United States of duplicity and chastising the outgoing Iranian president as naïve.

The remarks by the leader, Ayatollah Ali Khamenei, come as President Hassan Rouhani — an architect of the original nuclear accord — prepares to step down next week after eight years.

The fate of Iran’s negotiations with the United States to revive the accord, which have been suspended for more than a month, now falls to Mr. Rouhani’s successor, Ebrahim Raisi, an arch-conservative disciple of Mr. Khamenei.

The tone and timing of Mr. Khamenei’s remarks, which he delivered in person to Mr. Rouhani and his cabinet in a meeting reported by Iranian state media, amounted to a public rebuke of the departing president. They also sent a message that the negotiations are likely to face further challenges under Mr. Raisi.

“A very important experience in this period that the future generations should use is distrust of the West,” Mr. Khamenei said in lecturing the outgoing president and his aides, according to an account reported by Iran’s Fars News Agency.