Since the revolution, Iran has become more divided.
Iranians celebrated the 1979 overthrow of Shah Mohammad Reza Pahlavi, who was supported by the US, "waving Iranian flags, chanting "Death to America" and burning USA and Israeli flags", reported The Associated Press.
State TV showed crowds defying cold rainy weather and carrying Iranian flags while shouting "Death to Israel, Death to America", trademark chants of the revolution which ousted the United States' most important ally in the Middle East.
Addressing tens of thousands of people gathered on Tehran's Azadi (Freedom) Square on February 11, Rohani also said that Iran was determined to expand its military power and missile program despite mounting pressure from the United States and its allies.
Ballistic missile capabilities were on display during the main march, including the Qadr F, a ground-to-ground missile with a 1,950-km (1,220-mile) range, Tasnim news agency said.
In capital Tehran, demonstrators marched across different routes to reach the Azadi (Liberty) Square, where President Hassan Rouhani gave an address.
Trump said he envisioned keeping USA troops in Iraq "because I want to be able to watch Iran" during an interview with Margaret Brennan of CBS News that aired February 3.
One sign read, "Much to the dismay of America, the revolution has reached its 40th year". "It has been moving forward over the past 40 years and making Iran stronger". 40 years of terror.
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".
Israel and Iran have not maintained diplomatic relations since the Islamic Revolution of 1979.
Last year, Iran cracked down on protests over poor living standards.
U.S. President Donald Trump pulled out of Iran's 2015 nuclear deal with world powers past year and reimposed sanctions on Tehran, dealing a blow to the country's economy.
"I do not ignore the threats of the Iranian regime but neither am I intimidated by them", Netanyahu said in a statement and video issued by his office as Iran celebrated the 40th anniversary of its revolution. "The enemies are now confessing to their defeat", said Rouhani.
In January, President Hassan Rouhani said Iran was facing its worst economic crisis since the Shah was toppled.
A majority of Iranians blame domestic mismanagement and corruption over foreign sanctions for the economic situation, according to an IranPoll survey published in December 2018.
"The United States does not have the courage to shoot a single bullet at us despite all its defensive and military assets. But if they attack us, we will raze Tel Aviv and Haifa to the ground", Brig.
"Were this regime to make the awful mistake of trying to destroy Tel Aviv and Haifa, it would not succeed, but it would mean that they had celebrated their last Revolution Day. They should take that into account", Netanyahu said, as reported by Haaretz.
Citing leaked Iranian Judiciary documents, the Paris-based media watchdog also said that the authorities had arrested, imprisoned, or executed at least 860 journalists in the three decades between the 1979 revolution and 2009.
Today, Iran enjoys growing 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 that.