A sea of mourners stretched through the streets of Mashhad, Iran's holiest city, as the coffin of former Supreme Leader Ayatollah Ali Khamenei was carried to the Imam Reza Shrine. Officials said more than one million people were expected to attend.

Images from Mashhad showed people weeping, praying and accompanying the funeral vehicle throughout the route. Some participants displayed banners carrying threats against US President Donald Trump, reflecting the heightened tensions surrounding the ceremony.

The burial of Khamenei marks the end of an era in Iranian politics while taking place against the backdrop of one of the most serious confrontations between Iran and the United States in recent years.

The procession came at a particularly volatile moment for the region, with relations between Tehran and Washington deteriorating further in recent days. Security was visibly reinforced around the shrine as crowds filled nearby streets and squares.