Iran's President Hassan Rouhani speaks during a ceremony marking the anniversary of Iran's 1979 Islamic Revolution, in Tehran, Iran, Feb. 10, 2017. President.ir/Handout via REUTERS

Hundreds of thousands of Iranians rallied across the country Friday, burning effigies of U.S. President Donald Trump and chanting "Death to America" to voice their protest against the warning issued by the Trump administration last month, when Iran was put "on notice." The demonstrators also swore allegiance to the clerical establishment as Iran's president warned Friday that those in the U.S. using "threatening language" against Tehran would regret it.

Feb. 10 marks the anniversary of Iran's 1979 Islamic Revolution that toppled the U.S.-backed Mohammad Reza Shah Pahlavi. To commemorate this day, demonstrators in Tehran marched toward the Azadi (Freedom) Square. The people of Iran who gathered to celebrate the occasion had responded to a call from their Supreme Leader Ayatollah Ali Khamenei, who wanted his citizens to demonstrate that Iran was not frightened of threats posed by the U.S.

Iran's President Hassan Rouhani, who spoke at the march, also slammed Trump and his administration.

"This turnout is a response to false remarks by the new rulers in the White House and the people are telling the world through their presence that the Iranian people must be spoken to with respect," Rouhani said. "Iranians will make those using threatening language against this nation regret it."

Rouhani also asked more and more Iranians to join the rally to "show their unbreakable ties with the Supreme Leader and the Islamic Republic."

"Some inexperienced figures in the region and America are threatening Iran. They should know that the language of threats has never worked with Iran," Rouhani told the crowd at the Azadi Square. "They should learn to respect Iran and Iranians. We will strongly confront any warmongering policies."

Trump recently imposed fresh sanctions on Iranian individuals and entities in reaction to a missile test on Jan. 29. Iran, however, said it will not halt its missile programme.

State Television in Iran reported that millions came out on the streets and joined the rally in all the main cities, and that they all chanted anti-U.S. and anti-Israel slogans. It also showed footage of people stepping on Trump's photographs in Tehran.

"America and Trump cannot do a damn thing. We are ready to sacrifice our lives for our leader Khamenei," an unnamed young Iranian man told the state TV.

While thousands of Iranians chanted against Trump, many also thanked U.S. citizens who opposed Trump's executive order banning travelers from seven mostly Muslim countries, including Iran. They used the hashtag on Twitter that said "#lovebeyondflags."