UNITED NATIONS (AP) -- Iran's Parliament speaker said Thursday he expects a heated debate among Iranian lawmakers before they vote on the nuclear deal between his country and six world powers in about a month.

Ali Larijani, formerly Iran's top nuclear negotiator, predicted Iran's debate would be even more dramatic than the one now taking place in the U.S. Congress because of opposition from some members.

Iran's President Hassan Rouhani said last Saturday that he opposed a parliamentary vote on the agreement because its terms would turn into legal obligations if passed by lawmakers.

But Larijani said that according to the Iranian constitution, the agreement needs to be discussed and approved by the Iranian Parliament.

He said that's why a 15-member parliamentary committee is examining the deal, including its legality and the supervision and surveillance Iran will be under.

It will report to Parliament in a few weeks on its assessment, he said, "and I think Parliament will have to make its decision in about a month."

Larijani told a briefing for invited reporters that he personally believes "this deal is a positive thing - a good thing," but he wouldn't predict the result when Parliament votes.

The agreement calls for limiting Iran's nuclear program in exchange for lifting economic sanctions.

Iran insists its nuclear program is purely peaceful but the United States and Western nations believe Tehran's goal has been to produce nuclear weapons.

Larijani again accused the United State of playing "the role if a bully" during negotiations.

He said Iranian parliamentarians have found "serious and major faults" with the agreement including a mechanism for U.N. sanctions to "snap back" in place if any of the six powers - the U.S., Russia, China, Britain, France or Germany - determines that Iran is failing to meet its obligations.

"For us, this is not possible," Larijani said. "We cannot go back to the situation that we were in before the implementation of the agreement."

For example, the agreement requires Iran to redesign its nearly built reactor at Arak so it can't produce plutonium for nuclear weapons. But Larijani said "once you remove the core of the Arak reactor, you cannot put it back - this is impossible."

Nonetheless, Larijani said Iran also achieved some of its goals including being able to enrich uranium inside the country, despite limitations and restrictions. "Another success for us was the lifting of sanctions," he said.

By AP