Masoud Pezeshkian's victory in Iran's presidential elections has given a rare boost to efforts for scaling down years of tensions over Tehran's nuclear program, even with no indication of any upcoming breakthrough in the crisis.

Pezeshkian's defeat of ultraconservative Saeed Jalili, a former chief nuclear negotiator whose intransigence and style made him notorious among Western diplomats, is a relief for European governments as they seek to maintain dialogue on the issue.

The incoming president was backed by former President Hassan Rouhani, who, while in office, led efforts to defuse the crisis.