Waving Iranian flags, chanting "Death to America" and burning USA and Israeli flags, hundreds of thousands of people poured out onto the streets across Iran on Monday, marking the date that's considered victory day in the country's 1979 Islamic Revolution.
Iran's army declared its neutrality on February 11, 1979 which paved the way for the collapse of Shah Mohammad Reza Pahlavi - and ousted the United States' most important ally in the Middle East.
In an anniversary celebration in Tehran on Monday, Iranian President Hassan Rouhani took his own defiant stand against the United States, CNN reported.
"We have not asked, and will never ask for permission in developing our missile arsenal as we continue to pursue our path to military might", he added.
Iranians were also pictured burning numerous American flags as they celebrated the landmark anniversary in the country's capital.
One banner read: "Much to the dismay of America, the revolution has reached its 40th year".
Rouhani addressed the crowds for almost 45 minutes, lashing out at Iran's enemies - America and Israel - and claiming their efforts to "bring down" Iranians through sanctions will not succeed.
The event Monday is the culmination of official celebrations called the "10 Day Dawn" that mark the period between February 1, 1979 and February 11 when the revolution's leader Khomeini returned from exile and toppled the monarchy.
It was not clear whether the amnesty would also apply to political prisoners.
"It has been moving forward over the past 40 years and making Iran stronger".
Top political and military leaders in Iran regularly call for Israel's annihilation, with a senior general recently claiming it would defeat the Jewish state "within three days" in the case of a war.
He also blasted a USA "conspiracy" against the country, saying, "The presence of people today on the streets all over Islamic Iran. means that the enemy will never reach its evil objectives". "We will not let America become victorious." he said.
An anchor on state television warned of hostile foreign media trying to downplay the participation of Iranians in the march but expressed confidence that "they would be confounded by the unprecedented level of attendance".
Former public servant Saaghi insisted that it remained paramount for Iranians to stick by the revolution.
The large crowds at state-supported marches came as Iranians increasingly face economic hardship.
Iranian people gather during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran, Iran February 11, 2019.
Before the fireworks, supporters of the revolution shouted chants of "Allahu Akbar" (God is greatest) from rooftops, recalling the protests that swept Khomeini to power four decades earlier.