Tehran, Iran — A day after President Barack Obama secured enough votes to ensure approval of the Iranian nuclear deal in the U.S. Congress, Iran’s supreme leader, Ayatollah Ali Khamenei, on Thursday ordered parliament to vote on the agreement and threatened to cancel the pact entirely if the West merely suspended, rather than canceled, economic sanctions, state news media reported.

While the Iranian parliament is expected to approve the agreement, the announcement nonetheless represented a setback for President Hassan Rouhani and his nuclear negotiators, who have long held that the deal should be ratified by the Supreme National Security Council, which Rouhani heads. Their fear is that a debate in parliament will provide a platform for strident, archconservative opponents of the pact.

The head of parliament, Ali Larijani, who has been visiting New York for an international conference for speakers of parliaments, said Thursday that he expected more “drama” in his own legislature than in Congress over the nuclear deal.

Larijani said that a final decision was expected “in about a month,” which would most likely mean that it would not come before Rouhani arrives in New York for the annual meeting of world leaders at the U.N. General Assembly at the end of the month.

Rouhani is scheduled to address the General Assembly on Sept. 28, the same day as Obama.

Addressing a gathering of Shiite clerics in Tehran, Khamenei said that parliament “should not be bypassed” in the review of the nuclear deal, which would lift sanctions against Iran in exchange for a series of restrictions on the country’s nuclear program. As he has been all along, the supreme leader was careful not to tip his hand, saying it was up to the “representatives of the nation” to decide whether to accept it.

Nevertheless, Khamenei is widely seen as the architect behind the nuclear agreement, and analysts expect that lawmakers will support the deal, which has the public backing of Larijani.

Sounding a more cautionary note, Khamenei expressed doubt about whether the world powers would lift all of the sanctions and warned that Iran would cancel the deal if any of them remained in place.

“If we compromised on certain issues in the negotiations and conceded certain things, it was mainly to have the sanctions lifted,” he said. “If the sanctions are not to be lifted, there will not be a trade-off. Therefore, this issue has to be clarified.”

Khamenei blamed what he called “badly speaking American officials, who are making statements, saying the structure of the sanctions must remain intact.”

He seemed to be referring to Obama administration officials, who in defending the deal have emphasized that sanctions could be reimposed at any time if Iran is caught trying to conduct research or development on a nuclear weapon.

Khamenei urged Rouhani’s administration to counter such statements.

“Do not say that Americans are making these remarks to reassure their domestic rivals,” he said. “Of course, I believe that the domestic struggle in the U.S. is real.”

He added, “But, what is officially stated deserves to get a response. If it is not answered, then the statements of the other party become consolidated.”

In New York, Larijani said a 15-member parliamentary committee was expected to render its verdict soon, after which the parliament as a whole would decide whether to support the deal.

“I think the drama in my country will be bigger than that of yours,” Larijani said, speaking through an interpreter, during a meeting with about a dozen journalists at a hotel near the United Nations.

He told reporters that many of his fellow lawmakers objected in particular to the snapback mechanism that allows U.N. sanctions to be imposed automatically if Iran is shown to have breached its end of the deal.