Tehran's chief diplomat says some 'guiding principles' are agreed, but the supreme leader presents a different tone.

The second round of negotiations were held with mediation by Oman's Foreign Minister Badr bin Hamad al-Busaidi.

The second round of negotiations were held with mediation by Oman's Foreign Minister Badr bin Hamad al-Busaidi.

Iran's Foreign Minister announces agreement with the U.S. on guiding principles, paving the way for potential deal negotiations.

Tehran's chief diplomat says some 'guiding principles' are agreed, but the supreme leader presents a different tone.