The power to approve the nuclear deal will now rest with Rouhani, Ayatollah Ali Khamenei and the Supreme National Security Council
Iran's parliament curtailed its own power to block a nuclear deal with world powers on Sunday, effectively removing a longstanding threat that a final accord could be torn up by lawmakers.
A draft bill presented on Wednesday, which laid down strict criteria for Iran to accept any agreement, had threatened to complicate talks on a final accord, which are due to be finalised by 30 June.
However, in a boost to President Hassan Rouhani's government, key amendments to the proposed legislation will now move the formal supervision of a deal out of the hands of lawmakers.
The original text had set three key criteria that parliament would require to have been met for an agreement to be binding.
But the amended bill instead gives that right of supervision to the country's Supreme National Security Council (SNSC).
The council comprises government ministers, military commanders and other top officials appointed by Supreme Leader Ayatollah Ali Khamenei.
It is chaired by Rouhani, who is pushing hard for a nuclear deal, but is ultimately controlled by Khamenei, who will have the final word on any nuclear accord.
"Whatever decision the leader takes in this regard, we should obey in parliament," speaker Ali Larijani said after 199 MPs voted for the amendments in the 290-member chamber. "We should not tie the hands of the leader."
Only three lawmakers opposed the changes and five abstained, with six not voting and dozens more absent.
Although the sponsor of the original bill, Alaedin Boroujerdi, an MP and chairman of parliament's national security and foreign policy committee, said it was designed to insulate Iran's negotiators from the West's "excessive demands," Larijani suggested otherwise.
"We want to help the country and not create new problems," he said, referring to the need to coordinate with the SNSC, which had not had prior sight of the draft legislation but whose opinion was necessary.
According to the official IRNA news agency Larijani earlier told Ahmad Tavakoli, a conservative MP critical of the bill being delayed: "We are not discussing the sale of potatoes, but an important issue for the country."
Despite Sunday's changes, any nuclear deal will still have to be ratified by parliament but it would be highly unlikely by that stage that lawmakers would oppose any text approved by the SNSC.
The bill still requires the complete lifting of sanctions imposed on Iran as punishment for its nuclear programme under which the West suspected the Islamic republic of developing a bomb.
Iran denies any such aim and says its atomic activities are for purely peaceful, clean energy development purposes that would reduce its reliance on dirty fossil fuels.