Nov. 4 (UPI) -- Demonstrators gathered Sunday outside the former U.S. diplomatic mission, marking the 1979 takeover of the diplomatic complex known as the "den of spies" in the nation.
Nov. 4 is also known as Student Day and the National Day of the Fight against Global Arrogance.
Rallies also took place in more than 1,000 cities and towns in Iran, according to PressTV.
Participants chanted "Death to the U.S.", "Death to Israel" and "Never to Humiliation" in Persian.
The late founder of the Islamic Republic, Imam Khomeini, described the takeover as a "second revolution" after the 1979 Islamic Revolution toppled the Shah of Iran, a close ally of the United States.
This year's rallies come two days after U.S. President Donald Trump decided to reimpose all sanctions lifted under the 2015 nuclear deal with Iran. They take effect Monday.
Mohammad Ali Jafari, the commander of the Islamic Revolution Guards, told the marchers in central Tehran: "Never threaten the Iranian people ... do not make military threats against us, and do not frighten us from military threats."
He said "with God's assistance the Iranian nation will soon overcome economic sanctions." The commander added the United States is "on a gradual decline."
On Saturday, the IRGC issued a statement that the Iranian nation will give Trump a "slap in the face" through their participation in nationwide rallies marking the embassy takeover.
"The decline of the U.S. is a definite, inevitable reality consistent with a divine promise," the IRGC statement said.
The 13th of Aban on Sunday, the statement said, is "the symbol of the Iranian nation's fight against the arrogance and its invincibility in the face of the U.S. and the evil arrogant movement in contemporary history."
He also said: "There's a key fact here: in this 40-year challenge, the defeated is the U.S. and the victorious is the Islamic Republic."