Helicopter in convoy carrying Iranian president crashes - state media

Summary

1. A helicopter in a convoy carrying Iranian president Ebrahim Raisi has been involved in an accident, state media says
2. Reports say the helicopter - one of three travelling in a convoy - made a "hard landing" after it got into difficulties in heavy fog in the north of the country
3. Interior Minister Ahmad Vahidi said rescuers were still trying to reach the site, but that their efforts were being hampered by the poor weather conditions
4. Details of what exactly has happened remain unclear, and there's been no official confirmation of Raisi's whereabouts
5. Raisi was heading to the north-eastern city of Tabriz after returning from an Iran-Azerbaijan border area