TEHRAN, Iran — Hundreds of thousands of people poured out onto the streets of Tehran and other cities and towns across Iran on Monday, marking the date 40 years ago that is considered victory day in the country’s 1979 Islamic Revolution.
On Feb. 11 that year, Iran’s military stood down after days of street battles, allowing the revolutionaries to sweep across the country while the government of Shah Mohammad Reza Pahlavi resigned. It was also the day that Ayatollah Ruhollah Khomeini declared Iran an Islamic Republic.
In Tehran, crowds streamed in the rain from a dozen of the capital’s far-flung neighborhoods to mass in central Tehran Azadi, or Freedom Square, waving Iranian flags and chanting ‘‘Death to America’’ — a chant that has been standard fare at anti-U.S. rallies across Iran.
Downtown Enghelab, or Revolution Street, was decorated with huge balloons and loudspeakers blared out revolutionary and nationalist songs to encourage people to join the rallies. Iranian state TV ran archive footage of the days of the uprising and played revolutionary songs.
The festivities start every year on Feb. 1 — the day Khomeini returned home from France after 14 years in exile to become the supreme leader as Shiite clerics took power — and continue for 10 days, climaxing on Feb. 11.
This year’s anniversary comes as tensions rise with the United States and Iran is grappling with the aftermath of President Donald Trump’s pullout last May from the 2015 nuclear deal between Iran and world powers and also tough U.S. economic sanctions, re-imposed in November.
Speaking from a podium in central Tehran, Iranian President Hassan Rouhani addressed the crowds for nearly 45 minutes, lashing out at Iran’s enemies — America and Israel — and claiming that their efforts to ‘‘bring down’’ Iranians through sanctions will not succeed.
‘‘The presence of people in this celebration means that plots by the enemies ... have been defused,’’ Rouhani said. ‘‘They will not achieve their ill-omened aims.’’
Along with the chants ‘‘Death to America,’’ Monday’s marches were also a backdrop to the military’s display of Iranian-made missiles, which authorities showcase every year during the anniversary celebrations. Iran has missile capability of up to 2,000 kilometers (1,250 miles) — far enough to reach Israel and U.S. military bases in the region.
Over the past decade, Iran has frequently test-fired and displayed its Iranian-made missiles, sent several short-lived satellites into orbit and in 2013 launched a monkey into space.
The U.S. alleges Iran’s launches defy a U.N. Security Council resolution calling on Iran to undertake no activity related to ballistic missiles capable of delivering nuclear weapons. Tehran denies the charge, insisting its satellite launches and rocket tests do not have a military component.
‘‘We do not and we will not ask permission for producing any type of missiles from anybody,’’ Rouhani said in his speech, though he stressed that Iran would ‘‘continue constructive engagement’’ with the international community.
Rouhani also promised the crowds that Iran would overcome the economic hardship amid the country’s spiraling economy and the newly imposed U.S. sanctions.
One of the people in the crowd, 27-year-old medical student Hossein Hosseinpour, walked with his wife and their 18-month son Amir Ali. He said he wanted to teach his son to support the revolution.
‘‘I see a bright future for him and our nation,’’ Hosseinpour said.
Mahmoud Hemmati, 35, was pushing his 68-year-old mother, Parivash Fakheri, in a wheelchair, to the rally. ‘‘My mother, despite her illness, asked me to bring her out,’’ he said.
Fakheri, who was one of the revolutionaries on the streets of Tehran 40 years ago, said she would defend the revolt all over again.
‘‘I am a retired and I know there are many economic problems today, but that is something different from our revolution,’’ she said. ‘‘It has been moving forward over the past 40 years and making Iran stronger.’’
Last week, Supreme Leader Ayatollah Ali Khamenei defended the ‘‘Death to America’’ chants but said they are aimed at America’s leaders such as Trump and not its people.
The Iranian people ‘‘will not stop saying ‘Death to America’ as long as the U.S. 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.’’
Iranian state TV anchor Mehdi Khosravi chirped how he expects John Bolton, U.S. national security adviser, to be very angry on Monday since he had once predicted Iranians will not see the 40th anniversary of their revbolution.
Last year, Bolton told a meeting of Iranian exiles that ‘‘before 2019, we here ... will celebrate in Iran.’’