Campaigning for Iran's parliamentary runoffs next week began on Thursday, state radio reported, when allies of President Hassan Rouhani and their hardline rivals will compete to secure a majority after an inconclusive election earlier this year.
Rouhani supporters made big gains in a general election in February, especially in Tehran. They fell short of a parliamentary majority but won enough seats to ensure conservatives lost the upper hand in the house.
Rouhani's popularity has soared since signing a deal last year with world powers to curb Iran's nuclear program in exchange for lifting sanctions, a move that was largely opposed by anti-Western hardliners.
The race on April 29 could decide who will control the 290-seat house. Some 136 candidates will run for 68 seats representing constituencies where in February nobody secured a required 25 percent of votes.
"The campaigning started on Thursday and will continue until the next Thursday. There is no runoff vote in Tehran," state radio reported.
Although parliament lacks influence on Iran's foreign policy, a moderate majority could strengthen Rouhani's hand in his bid to open Iran further to foreign investment following lifting of sanctions in January.
In February, conservatives won about 112 seats in parliament, reformers and centrists 91 seats and independents and religious minorities 18 seats, a tally by Reuters showed, compiled in the absence of official numbers.
In a big win, a reformist-backed list of candidates aligned with Rouhani won all 30 parliamentary seats in Tehran.
Iran lacks rigid party affiliations and some candidates are backed by more than one political camp, which makes it difficult to specify which faction has won a parliamentary majority.
Complicating next week's runoffs are the disqualifications of thousands of moderate candidates, including almost all prominent reformists, by the Guardian Council, a hardline vetting body.
"We have prepared a list for the runoff vote. It was difficult because in some constituencies we were left with no choice because of the disqualifications," said a prominent reformist in Tehran who asked not to be named.
Rouhani and his allies also won 15 out of the 16 Tehran seats in the 88-member Assembly of Experts in February. The assembly selects the supreme leader, the person with the most clout in Iran.
The new parliament and the Assembly of Experts will start work on May 27.