TEHRAN, Iran 

A key Iranian reformist figure and former political prisoner Mostafa Tajzadeh on Friday filed his nomination for the forthcoming presidential election.

Tajzadeh, one of the strongest pro-reform voices in Iran, earlier announced he would be running for the presidency, despite a new directive issued by the country's top vetting body, the Guardian Council.

According to the new directive, which President Hassan Rouhani has already rejected, a person with a jail record cannot run for the country's top political post.

Tajzadeh spent seven years in an Iranian prison following the 2009 election that reformists said was rigged. He was accused of acting against the country's security.

After registering for the June election, the former lawmaker said he opposes compulsory veil, is against the present ruling system's method, and is in favor of dialogue with the US.

Tajzadeh is one of the 14 names proposed by Iran's reformist camp as a probable presidential candidate. Observers, however, say he is most likely to face rejection during screening process by the Guardian Council after five-day registration period ends.

Among other prominent reformist figures expected to register on Friday or Saturday are Vice President Ishaq Jahangiri and Tehran city council head Mohsen Rafsanjani.

Foreign Minister Javad Zarif has already turned down calls to contest the election.

Meanwhile, Fereydoon Abbasi, the former chief of Iran's nuclear agency and one of the nuclear scientists targeted in 2010, also filed his nomination.

In the conservative camp, the buzz is that judiciary chief Ebrahim Raeisi is likely to announce his candidature, which would force other conservatives to withdraw in his favor.