Mahmoud Ahmadinejad today stunned Iran by unexpectedly filing to run again as leader in the country's forthcoming election.
The decision by the former hardline president could upset an election which many believed would be won by President Hassan Rouhani, a moderate who negotiated the country's nuclear deal with world powers.
Though Rouhani has yet to formally register for the election race, many viewed him as a shoo-in after Supreme Leader Ayatollah Ali Khamenei's recommendation in September that Ahmadinejad stand down, and because of the conservatives' inability to coalesce around a single candidate.
Registration for the May 20 election began on Tuesday and will last five days, after which candidates will be screened for their political and Islamic qualifications by the Guardian Council, a vetting body.
President Hassan Rouhani, whose 2015 nuclear deal secured a removal of international financial and trade sanctions against Tehran, is expected to seek re-election but faces a stiff challenge from conservatives who opposed the deal.