Enormous crowds assembled outside the funeral for the late Iranian supreme leader once the entrances to the vast Grand Mosalla mosque in central Tehran admitted thousands of mourners who had waited through the night for entry to the complex.

Iran has organized large-scale funeral processions for Ali Khamenei whose 37-year rule ended in February with the first airstrike of the conflict begun by the US and Israel. By 5:30am the streets of Tehran around the mosque were already filling with Iranians some of whom traveled for hours many carrying flags or posters of Khamenei as they headed toward an event intended to underscore national grief over the supreme leader's killing and a wish for retaliation. The mood was intense as participants chanted slogans against America and Israel.

Khamenei aged 86 was killed by Israeli aircraft and the elevated platform displaying his coffin also held the remains of other relatives lost in the strike including his 14-month-old granddaughter.

By 8am the open-air mosque held around 10,000 people divided equally with men positioned on the right and women on the left.

The scope of the six-day five-city funeral was planned to convey messages of political and religious resistance internationally. Organizers state that as many as 30 million people could take part at various stages. At the urging of Iraqi officials Khamenei's remains will also pass through the Shia cities of Karbala and Najaf in Iraq.

The banner placed near the bodies stated: Say I only advise you with one thing that you stand up for Allah singly or in pairs. Prior to the religious segment of the ceremony the main sounds were cymbals and tambourines along with repeated calls of Death to America and Death to Israel.

While religious songs the national anthem and tributes to martyrs filled the air even in press zones distressed men sat cross-legged striking their chests or sobbing heavily with shoulders shaking. Nearby journalists managed their social media accounts taking selfies that captured the large crowd behind them.

Authorities concerned about past overcrowding at Iranian funerals advised attendees not to linger too long inside the mosque. By midday as temperatures hit 36C attendance had decreased.

Banners across nearby streets proclaimed Khamenei's martyrdom and lasting role in Iranian history. Yellow Hezbollah flags appeared among participants while the Iranian flag was draped over shoulders like attire for a sports event.

Hundreds of mokebs food stations provided free boiled eggs halim soup with cinnamon lemonade watermelon kebabs tea and countless plastic bottles of water. Helpers rested in schools cars or tents overnight. Donations for the needy could be made by credit card at stations. Water mist sprays helped cool the gathering. At one booth students allowed visitors to pose for photos beside an image of the new supreme leader the son of Ali Khamenei.

One woman Fatima Khavari remarked that she felt crushed upon learning of the leader's death noting he was the sole true guide known to her. A university professor at another stand questioned US involvement in the Middle East asking how it would feel if outsiders came to seize minerals and target leaders.

On streets near the mosque music both revolutionary and religious began playing from rival sound systems well before sunrise. Men distributed posters declaring We are the revenge seekers of Ali Khamenei.

British and American journalists received official guidance against interviewing mourners yet most participants were eager to speak often to highlight differences between US president Donald Trump described in various terms as a megalomaniac and their own martyred scholarly leader.

One cleric in a white turban Hossein Ajorlu standing outside the mosque compared the figures to a brush used for cleaning toilets that becomes soiled and clean spring water of renewal.

He seemed surprised at any notion that the military might be overtaking the clergy's role in Iran.

The attendees at the mosque reflected one segment of Iranian society with all women wearing the chador a full-body cloak while in daily settings more than half the women in Tehran do not wear the hijab.

Not every Iranian participated in what one called a victory parade. Roads leaving Tehran on Thursday remained busy despite official encouragement to join the farewell. One recent returnee from the US who chose to stay in the capital described the event as not his thing. An admirer of US secretary of state Marco Rubio he noted that Trump should have completed the initial action yet appeared inconsistent believing Iran resembled Venezuela though this government rests on deep roots including religion.

The country faces serious challenges with shop prices shifting daily and occasional shortages of essentials. A society cannot endure such conditions even if a government might.

The government will need to assess whether the postponed funeral truly helps reunite and redirect a nation partly divided by Khamenei's conservative religious governance.

The ceremony's scale has overshadowed reports that France and Britain may dispatch warships to address mines in the strait of Hormuz. Khamenei spent much of his life preserving Iran's independence from the US and that contest continues beyond his passing.