TEHRAN, Iran — Iran on Saturday started registering potential candidates for the country's March parliamentary elections, a vote that will be fought between supporters and opponents of President Mahmoud Ahmadinejad.

The country's major reformist groups are staying out of the race, saying they won't field any candidates because basic requirements for free and fair elections have not been met.

In their absence, the poll for the 290-seat assembly is likely to pit hard-line candidates who remain staunchly loyal to the country's Supreme Leader Ayatollah Ali Khamenei against conservatives who support Ahmadinejad.

Whatever the outcome, the vote is unlikely to change Iran's course. The country is a theocracy and Khamenei has final say on all state matters.

The March 2 elections will be the first nationwide balloting since Ahmadinejad's disputed re-election in 2009, which the opposition said was heavily rigged. That vote set off months of near-daily protests, when hundreds of thousands took to the streets in support of opposition leader Mir Hossein Mousavi who they claimed was the rightful winner.

The wave of protests was the biggest challenge to Iran's clerical leadership since it came to power in the 1979 Islamic Revolution. But a heavy crackdown suppressed the protests, and many in the opposition — from midlevel political figures to street activists, journalists and human rights workers — were arrested. The opposition has not been able to hold a major protest since December 2009.

For the March elections, the Interior Ministry is in charge of the weeklong registration process, which started Saturday. All Iranian nationals between 30 and 75 years of age who have "proven themselves to be loyal" to Khamenei are allowed to run. Once submitted, candidacies have to be approved by the hard-line constitutional watchdog, the Guardian Council.

The council's chief, Ayatollah Ahmad Jannati, has earlier said the reformists, whom he called traitors, need not participate. His position was widely seen as an indication the hard-line body would disqualify anyone perceived as a reformist from running.

In the previous, 2008 parliamentary elections, the council disqualified thousands of reformist candidates.

Recently, Iran's former reformist President Mohammad Khatami demanded that political prisoners be freed and that Mousavi and another opposition leader, Mahdi Karroubi, be released from house arrest. Khatami said those were preconditions for reformists participating in the March polling. None have so far been met.

Ali Mohammad Gharibani, a prominent reformist leader, confirmed last week that the reformists will stay out of the race.

"Despite efforts ... to create an appropriate election climate, unfortunately more restrictions have been imposed," said Gharibani, who runs the Reformist Front Coordination Council. "Therefore, the council has decided that it won't issue any election list and won't support anyone."

Hard-liners say the threat to the ruling system now comes from Ahmadinejad's supporters. The president has been the target of a backlash since April for trying to impose too much autonomy in how the government is run, including defying Khamenei on his choice for the powerful post of intelligence minister.

Dozens of Ahmadinejad's allies have been detained over the past months — including four senior government officials last week — in the evolving power struggle.