Iranian President-elect Hassan Rowhani speaks to the press following a visit to the Khomeini mausoleum, in Tehran on June 16, 2013.

Moderate cleric Hassan Rohani won Iran's presidential election on Saturday, the interior ministry said, scoring a surprising landslide victory over conservative hardliners without the need for a second round run-off.

The outcome will not soon transform Iran's long tense relations with the West, resolve an international crisis over its pursuit of nuclear power or lessen its support of Syria's president in the civil war there—matters of national security that remain the domain of Supreme Leader Ayatollah Ali Khamenei.