Iranian President Hassan Rouhani casts his vote during elections for the parliament and Assembly of Experts, which has the power to appoint and dismiss the supreme leader, in Tehran February 26, 2016. REUTERS/President.ir/Handout via Reuters

President Hassan Rouhani and his allies won big gains in Friday’s twin Iranian elections that could develop Iran’s engagement with the world after his government ended years of sanctions by agreeing to curb its nuclear program.

Final results for the Tehran constituency on Monday were a humiliating blow to the conservative Islamic establishment, which retains decisive power due to Iran’s dual system of clerical and republican rule.

Unexpected gains by moderates and reformists in both elections are considered a strong vote of confidence to Rouhani, which will significantly increase his chances of seeking re-election in 2017.

Reformist-backed candidates took all but one seat in the assembly and enjoyed a clean sweep of all 30 seats allocated to Tehran in the 290-seat Iranian parliament, the Majlis. Mohammad Reza Aref, a devoted reformist who has a degree from Stanford University in the US, is at the top of the list. Gholam-Ali Haddad-Adel, a hardliner close to Khamenei, whose name topped the list of “principalist” candidates, lost his seat in the parliament.

Most of the lawmakers who did not make it to the new parliament sturdily opposed the nuclear deal, including Mehdi Koochakzadeh, who called Foreign Minister Mohammad Javad Zarif “a traitor”, and Roohollah Hosseinian, who threatened to bury the negotiators under cement for agreeing to concessions to world powers.

“This election can be a turning point in the history of the Islamic Republic,” said an editorial in reformist newspaper Mardom-Salari, whose managing editor, Mostafa Kavakebian, won a parliamentary seat in Tehran.

“The biggest achievement of this election is the return of reformists to the ruling system … so they won’t be called seditionists or infiltrators anymore,” he said, referring to conservatives who accused reformists of links to the West.

According to final election results for Tehran, Rouhani and allied centrists and reformers won 15 out of the 16 Tehran seats in the 88-member Assembly of Experts, which is responsible for choosing the country’s next supreme leader.

Two prominent conservatives, including the speaker of the powerful clerical body, were among those ousted in the capital.

Candidates on the reformist list also took all 30 parliamentary seats in the Tehran constituency, up from just two previously, final results released by Interior Minister Abdolreza Rahmani Fazli showed.

While conservatives still keep hold of many seats in both bodies, the assembly’s results are in favor of the reformists not because reformist candidates are stepping into the clerical body but because of alliances with successful moderate-leaning candidates.

The twin polls, for the assembly and parliament, were seen by analysts as a pivotal moment for Iran after years of isolation, and a vote of confidence in Rouhani’s government and his detente policy with the West.