Holding Iranian flags and portraits of the founder of the Islamic republic, the late Ayatollah Ruhollah Khomeini, crowds converged on Tehran’s central Azadi (Freedom) Square, where President Hassan Rohani is set to deliver a speech later on February 11.
Participants carried banners with slogans such as “Death to America” and “We will resist until the end.”
State TV showed video footage of rallies in other cities including Mashhad, Ahvaz, and Kerman.
The annual celebrations mark the day when Khomeini followers ousted the last government of U.S.-backed Shah Reza Pahlavi, heralding the start of four decades of clerical rule in Iran.
This year’s anniversary comes amid heightened tensions with Washington, which in 2018 withdrew from a nuclear agreement between Tehran and world powers and reimposed tough sanctions on the Iranian economy. Tehran has gradually stepped back from its own commitments under the 2015 deal and said this year it no longer considered itself bound by it.
Tensions escalated in early January after the killing of Iranian Major General Qasem Soleimani, the leader of Iran’s elite Quds Force, in a U.S. air strike Baghdad.
In reprisal, Tehran launched missile strikes on two bases hosting U.S. troops in Iraq. The Pentagon says 109 U.S. service members have been diagnosed with mild traumatic brain injury following the attack on Ain al-Asad Air Base in western Iraq.
Soleimani’s daughter Zeinab was to address the rally in Tehran on February 11.
The anniversary also comes ahead of Iran’s parliamentary elections on February 21 that are expected to gauge the popularity of Rohani and his camp, a mixture of moderate and pro-reform factions.
Rohani’s government has come under intense pressure from conservatives for agreeing the 2015 nuclear accord that exchanged curbs on Iran’s nuclear program for sanctions relief.
Meanwhile, public anger has risen in recent months as Washington continued its campaign of “maximum pressure.”
When officials announced gasoline rationing and price hikes in November, anti-government protests erupted in more than 100 Iranian cities and turned violent before security forces put them down amid an Internet blackout.
The crash of a Ukrainian passenger plane after takeoff from a Tehran airport last month also triggered public anger.
Iranian authorities initially denied any responsibility for the accident, in which all 176 people aboard the jet were killed. But three days after the tragedy the Islamic Revolutionary Guards Corps admitted the plane had been shot down “unintentionally” by the country’s air defenses.