Coffin of Iran president arrives at Tehran airport

Tens of thousands of Iranians gathered Tuesday to mourn President Ebrahim Raisi and seven members of his entourage who were killed in a helicopter crash on a fog-shrouded mountainside.

Waving Iranian flags and portraits of the late president, mourners set off from a central square in the northwestern city of Tabriz, where Raisi was headed when his helicopter crashed on Sunday. Iran's armed forces chief of staff Mohammad Bagheri ordered an investigation into the cause of the crash as Iranians in cities nationwide gathered to mourn Raisi and his entourage.