The debate on Monday was the first of five planned in the 10 days remaining before the vote in a shortened campaign to replace Raisi, a hard-line protégé of Supreme Leader Ayatollah Ali Khamenei once floated as a possible successor to the 85-year-old cleric

The candidates were to discuss their proposals and plans for Iran's spiralling economy, struggling under sanctions from the United States and other Western nations

They all promised they would try and get the sanctions lifted and introduce reforms but none offered any details. The candidates also discussed inflation, the budget deficit, Iran's housing problem and ways to fight corruption

The June 28 election comes at a time of heightened tensions between Iran and the West over Tehran's rapidly advancing nuclear programme, its arming of Russia in that country's war on Ukraine and its wide-reaching crackdowns on dissent

Iran's support of militia proxy forces throughout the wider Middle East, meanwhile, have, been increasingly in the spotlight as Iran-backed Yemen's Houthi rebels attack ships in the Red Sea over the Israel-Hamas war in the Gaza Strip

Five of the candidates are hard-liners while the sixth candidate, lawmaker Masoud Pezeshkian, 69, is a heart surgeon who has the support of some pro-reformers

The most prominent candidate remains Mohammad Bagher Qalibaf, 62, a former Tehran mayor with close ties to the country's paramilitary Revolutionary Guard. However, many remember that Qalibaf, as a former Guard general, was part of a violent crackdown on Iranian university students in 1999. He also reportedly ordered live gunfire to be used against students in 2003 while serving as the country's police chief

Among those running for president are also Iran's vice-president, Amir Hossein Qazizadeh Hashemi, 53, and the current Tehran mayor, Ali Reza Zakani 58. A member of Supreme National Security Council, 58-year-old Saeed Jalili and cleric Mostafa Pourmohammadi, 64, a previous interior minister under former relatively moderate President Hassan Rouhani, are also in the race

Qalibaf promised he would be a "strong" president who would support the poor, better manage the economy and effort to remove sanctions through diplomatic means