According to Islamic tradition, Friday prayer leaders - or imams - address worshippers at the weekly communal prayers on the issues of the week.

The tradition had died down and become largely a ceremonial affair under the rule of the Shah.

But the late Ayatollah Khomeyni, the founder of the Islamic Republic of Iran, revived the Friday sermons.

Rifle in hand

Friday prayers have since become the platform from which Iranian leaders announce policy or pronounce views on major domestic and international issues.

The sermons are broadcast live on Iranian radio.

The first Friday imam of Tehran after the revolution was the late Ayatollah Taleqani.

It was this popular cleric who began the tradition - observed to this day - of the imam addressing the congregation while holding a rifle in one hand.

Assassination attempt

It was supreme leader Ayatollah Khamenei who took to the podium this Friday at the grounds of Tehran University to deliver the sermons to the capital's congregation.

Khamenei, who was appointed by Khomeyni as the official Friday imam of Tehran, appears at the Friday podium only on special religious or political occasions.

Other senior leaders usually act as the Friday imam of Tehran.

But being a Friday imam in the early days of the revolution was a dangerous affair.

The Iraq-based opposition Mojahedin-e Khalq Organization assassinated five Friday prayer imams while they were delivering the sermons.

They became known as "martyrs of the altar" .

And Khamenei himself nearly joined the rank of these martyrs when he was the target of an assassination bid which left him paralysed in one hand.

"I remember standing at this very spot when the explosion took place," he told the crowd.

"We first thought it was an missile or aerial attack, I became worried that the Friday prayers would fall apart."

He then recounted how the people did not show any fear while the bodies of the dead were taken away.

The prayers then continued.

"It was you the people that guarded the Friday prayers, and the Friday prayers of Tehran became the symbol of prayers across the country."