Hundreds of thousands of people have taken to the streets of Tehran and other Iranian cities to take part in state-sponsored anti-Israeli rallies marking the annual Quds Day, state media report.
Some protesters set Israeli and U.S. flags on fire, reports said on June 23, while others chanted "Death to America" and "Death to Israel."
Iran doesn't recognize Israel and backs militant groups such as Hamas in the Gaza Strip and Lebanon's Shi'ite Hizballah militia. Both Hamas and Hizballah have been designated terrorist organizations by the U.S. State Department.
The United States and its ally Israel accuse Iran of supporting terrorism and of fomenting unrest across the Middle East.
The demonstrators also chanted against the Saudi royal family and the extremist group Islamic State (IS).
Quds Day, referring to a historic Arabic name for Jerusalem, was established by the founder of the Islamic republic, Ayatollah Ruhollah Khomeini, to show support for Palestinians and opposition against Israel.
This year's commemoration follows deadly attacks in Tehran that were claimed by the IS group.
It also comes amid an intensifying battle for influence in the region between Shi'ite Iran and its Sunni-ruled rival, Saudi Arabia.
Marchers in Tehran converged from various points of the city onto the Friday Prayer ceremony at Tehran University.
Similar demonstrations were being held in cities across Iran, according to state media.
Addressing the crowd in the capital, parliament speaker Ali Larijani called Israel the "mother of terrorism," saying it had displaced "millions of Muslims."
President Hassan Rohani, who joined the march through Tehran, told state TV that this year's rally "shows people want our region to be cleaned up from terrorists, backed by the Zionist regime," which is how Iranian officials label the Israeli government.
Rohani also hit out at an Iran sanctions bill approved by the U.S. Senate earlier this month.
"With the anti-Iranian bills presented in the U.S. Senate and House of Representatives, the Iranian nation wants to tell America through this rally that the government will respond with determination and will continue the path it has chosen," he said.
On June 15, the Senate overwhelmingly supported further sanctions against Iran for its alleged "continued support of terrorism." Congressional committees are currently working to resolve a procedural issue blocking the bill at the House of Representatives.
Friday Prayer leader Ayatollah Ahmad Khatami said the bill violated the July 2015 deal between Iran and world powers, under which international sanctions against the country were lifted last year in return for curbs on the country's nuclear activities.
Iran's ballistic-missile program has been the subject of constant concern in the United States and Israel and the target of U.S. sanctions.
Also on June 23, authorities in Tehran displayed three surface-to-surface ballistic missiles, including the Zolfaghar missile that Iran said it used this week against IS targets in Syria.
Iran, a key backer of Syrian President Bashar al-Assad, has been heavily involved in the war against the IS group in both Iraq and Syria where it is backing Shi'ite militias in their fight against the Sunni extremists.
On June 18, Iran's Islamic Revolutionary Guard Corps (IRGC) said it launched six Zolfaghar missiles from western Iran into the Deir al-Zour region of eastern Syria, killing a "large number" of "terrorists."
The move came after 17 people were reported killed and more than 40 wounded in attacks on the Iranian parliament and the shrine of Khomeini on June 7 -- the first major attacks in Iran for which the IS group has claimed responsibility.
Iranian officials have since repeated accusations that Saudi Arabia funds Islamic militants, including IS.
The Saudi monarchy, an ally of the United States, denies involvement in the attacks.