Mourners began gathering for days of funerals and processions for Iran's late president, foreign minister and others killed in a helicopter crash Sunday.

The Iranian government began funeral proceedings Tuesday for its late president, foreign minister and other officials killed in a helicopter crash, as the country attempts to regain footing after the deaths left the Islamic Republic with an uncertain future.

Iran began funeral processions Tuesday for President Ebrahim Raisi, as the country grapples with the fallout from his sudden death at a time of heightened regional tensions and domestic uncertainty.Supreme Leader Ayatollah Ali Khamenei has declared five days of national mourning for Raisi,

Iran began five days of nationwide mourning on Tuesday with a massive funeral procession following the sudden death of President Ebrahim Raisi who died in a helicopter crash Sunday. NBC’s Keir Simmons reports for TODAY.

Funeral ceremonies for Iran's President Ebrahim Raisi came as investigators said they still don't know what caused a helicopter he was traveling in to crash.

Thousands of Iranians turned out to mourn President Ebrahim Raisi in the city of Tabriz on Tuesday, after he was killed in a helicopter crash near the Azerbaijan border at the weekend along with his foreign minister and seven others.

Funeral events for Iran's president and foreign minister got underway Tuesday with a procession on the streets of the northwestern city of Tabriz, while investigators launched a probe into the deadly helicopter crash.

Iran will kick off funeral ceremonies for the late Iranian president Ebrahim Raisi on Tuesday following his death in a helicopter crash as authorities probe what caused the aircraft to smash into the side of a remote mountainside.