Along with the chants "Death to America" and banners bearing slogans calling for "Death to Israel", Monday's marches were also a backdrop to the military's display of Iranian-made missiles, which authorities showcase every year during anniversary celebrations.
People across Iran are taking to the streets today to mark the 40th anniversary of its Islamic Revolution - an event that has gone on to define the country and its position within the world.
In the backdrop to Monday's marches, the military displayed Iranian-made missiles, which authorities showcase every year during anniversary celebrations and which now have a range of up to 2,000 kilometres (1,250 miles) and are able to Israel and US military bases in the region.
The Shah was the United States' closest ally in the Middle East.
The large crowds at state-supported marches came as Iranians increasingly face economic hardship.
That April, the Islamic Republic of Iran was proclaimed following a referendum. 40 years of repression.
The Iranian people "will not stop saying "Death to America" as long as the USA acts malicious" toward Iran, Khamenei said, referring to Trump's State of the Union address in which the American president, among other things, said: "We will not avert our eyes from a regime that chants death to America". The demonstrations posed the most serious challenge to its clerical leadership since a 2009 uprising over disputed elections. Iranian people have and will have some economic difficulties but we will overcome the problems by helping each other, ' Rouhani said.
"Iran has changed from a backward nation to a world power", said the 50-year-old.
Yadollah Javani is the Revolutionary Guards' assistant head for political affairs.
Prime Minister Benjamin Netanyahu on Monday threatened the Iranian regime with destruction after an Iranian military leader warned that the Islamic Republic would raze major Israeli cities if the U.S. attacked it. "I am not ignoring the threats of the Iranian regime, but nor I am impressed by them", he said.
"If this regime makes the bad mistake of trying to destroy Tel Aviv and Haifa, it will not succeed", the Israeli leader said. "They should take this into account", Netanyahu said in a warning to his country's archfoe.
An Iranian woman carries a picture of Iran's Supreme Leader Ayatollah Ali Khamenei during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran, Iran February 11, 2019.
In his address on Tehran's Azadi Square, Rohani said the "enemy will never reach its evil objectives", vowing that Iran will defeat USA sanctions.
Today, Iran enjoys influence through proxies in Iraq, Syria, Lebanon and Yemen, raising concerns in Sunni Saudi Arabia, which accuses its rival of trying to dominate the Middle East. Tehran denies the allegations.
Cleric Hossein Firouzi told AFP Iran's revolution had achieved everything it set out to in terms of military power, political identity and scientific achievements.