President Mahmoud Ahmadinejad said on Saturday that Iran's Islamic revolution was not limited to its borders, as the country paid tribute to the man who led the overthrow of the shah 30 years ago.
"The revolution is lively and alive after 30 years," Ahmadinejad said at a ceremony marking the anniversary of the return from exile of the father of the revolution Ayatollah Ruhollah Khomeini.
"We are still at the beginning of the path and greater changes are ahead. This thunderous revolution will continue until justice is implemented," the firebrand president said.
"Although the Islamic revolution happened in Iran it is not limited to Iranian borders."
Ahmadinejad was joined at the ceremony at Khomeini's mausoleum in southern Tehran by supreme leader Ayatollah Ali Khamenei as well as members of the government and military commanders.
Each year, to mark Khomeini's triumphant return after 15 years in exile, all schools, trains and boats ring their bells at precisely 9:33 am, the moment his plane touched down on February 1, 1979.
The country is holding 10 days of celebrations marking the 30th anniversary of the overthrow of the US-backed shah, who ruled Iran for almost four decades but fled just two weeks before Khomeini's return.
Khomeini's shrine was decorated with a large poster of the elderly bearded cleric, then 76, as he disembarked from an Air France jumbo jet helped by a steward -- an image etched in world history.
The revolution led to the installation of a hardline clerical government that has become increasingly isolated on the world stage.
"The Islamic revolution is the result of sacrifices made by martyrs," read a banner inscribed with one of Khomeini's famous quotes.
"We will guard the great legacy and principles of Imam Khomeini," vowed Khamenei on another banner of his mentor who died in 1989.
A group from the hardline Basij militia on Friday washed Khomeini's tomb with rose water -- an Iranian custom to honour the dead -- and the grave was later strewn with flowers, state television said.
This year's anniversary celebrations come barely four months before a presidential election in Iran, with Ahmadinejad seeking re-election for another four-year term.
Khomeini arrived in Tehran on February 1 but his return is being celebrated on January 31 this year because it is a leap year in the Iranian calendar.
Khomeini backed Islamist students who stormed the US embassy in Tehran in November 1979 and took its personnel hostage for 444 days, prompting Washington to severe ties with the Islamic republic.
Tension with the United States has soared over Iran's contested nuclear drive, which many in the West fear is a cover for a secret atomic weapons programme.
Khomeini branded the United States as the "Great Satan", and Iran was lumped in the "axis of evil" by former US president George W. Bush.
New US President Barack Obama has said he is willing to extend a diplomatic hand to Tehran if it is ready to "unclench its fist".
In response, Ahmadinejad launched a fresh tirade against the United States, demanding an apology for its "crimes" against Iran and saying he expected "deep and fundamental" change from Obama.