Over 230 dissidents and civil society activists in Iran have called on fellow citizens to boycott the country's presidential election slated for June 18.

In an open letter addressing the Iranian nation, the signees described the election as little beyond a "formality." The activists demanded that Supreme Leader Ayatollah Ali Khamenei step down as the first stage in a peaceful transition from a system led by a cleric to a secular state compliant with the United Nations Charter. "Let's boycott the show election so that the unpopular establishment will not endure," the letter reads.

Expressing pride about their diversity, the dissidents said they represented a "rainbow" of political leanings and ethnicities from across Iran. Among the notables behind the letter are well-known former political prisoner Heshmatollah Tabarzadi, jailed journalist Mohammad Nourizad and teachers union activist Javad La'l-Mohammadi.

Last week, some 600 candidates registered for the key polls. Members of the hard-line Guardian Council, who are either directly or indirectly appointed by the supreme leader, are in charge of vetting the candidates, whose final list is due this week. Speculation is rife that the main battle will be waged between judiciary chief Ibrahim Raisi and former parliament speaker Ali Larijani.