The 80-year-old Mr Khamenei, who has held the country’s top office since 1989 and has the final say on all major decisions, is also throwing his support behind the elite Revolutionary Guards after their belated admission that they had downed an airliner in error sparked days of rage on the streets. But the supreme leader also said the US should leave the region and the President Donald Trump was a “clown” who will “push a poisonous dagger” into the nation’s back by only pretending to care about Iranians.
Mr Trump, who pulled Washington out of a nuclear deal with Iran in 2018 and started the latest escalation that briefly resulted in open conflict this month, had tweeted support for protesters in both English and Farsi.
State television showed queues of buses that were taking people to attend the ceremony in central Tehran.
The prayers usually take place around midday on Friday in Iran.
The Ukrainian passenger plane was shot down on January 8 in the tense hours after Iran launched missiles at US targets in Iraq in response to a US drone strike on January 3 that killed powerful Iranian general Qasem Soleimani, who was close to Khamenei.
Vigils for the 176 victims swiftly turned into protests against Iran’s rulers.
“Death to Khamenei” was chanted at protests and also spray painted on walls of Tehran and other cities. Such public criticism can result in a jail term in Iran.
During his speech, Mr Khamenei said Iran has cooperated “beyond expectations” with countries whose citizens were killed in the Ukrainian plane crash.
He added millions of people in Iran and thousands in Iraq mourned Soleimani and the day Iran retaliated by attacking Us targets in Iraq was a “day of God”.
READ MORE: The real reason behind Trump’s kill order of ‘total monster’
And Iran “enemies” used the plane crash to “weaken Iran Revolutionary guards”.
And there was also strong criticism for “European powers for triggering nuclear dispute”.
The supreme leader then said the three European parties in the nuclear deal “cannot be trusted”.
He claimed France, Britain and Germany are “serving US interests”.
He added: “Iron hands of European negotiators are hidden under velvet gloves”.
He also added Iran is not against negotiations with anyone except the US.
Through an Arabic translator, Mr Khamenei said the US is trying to divide Iraq and trigger civil war.
He said Iran’s retaliatory missile attack on US troops in Iraq earlier this month was a “blow to America’s image” as a superpower.
Finally, the supreme leader called for national unity and a high turnout in the February election.
Tensions between Iran and the United States have steadily escalated since President Donald Trump withdrew the US from Iran’s 2015 nuclear deal with world powers, which had imposed restrictions on its nuclear programme in exchange for the lifting of international sanctions.
The White House has since imposed crippling sanctions on Iran, including its vital oil and gas industry, pushing the country into an economic crisis that has ignited several waves of sporadic, leaderless protests.
Mr Trump has openly encouraged the protesters, even tweeting in Farsi, hoping that the protests and the sanctions will bring about fundamental change in a long-time adversary.
After Mr Soleimani was killed in a US airstrike in Baghdad, Iran announced it would no longer be bound by the limitations in the nuclear agreement.