The last time Ayatollah Ali Khamenei led Friday prayers at Tehran's Mosalla mosque was in February 2012, on the 33rd anniversary of the Islamic revolution and at a time of crisis over the Iran nuclear issue.

His latest appearance comes at a tumultuous moment for the country, which had seemed headed for conflict earlier in January after the United States killed its foreign operations chief in a Baghdad drone strike, prompting retaliatory Iranian missile strikes against Iraqi bases housing US troops.

The strikes, which caused significant material damage, wounded 11 US troops, US Central Command said Thursday, contradicting previous reports from the military of no casualties.

Earlier in the day President Hassan Rouhani emphasised in a televised speech that Iran "is working daily to prevent military confrontation or war", and maintained that a dialogue with the world was still "possible".

Tensions between Washington and Tehran have abated since Iran's admission it accidentally downed a Ukrainian airliner when it was high alert after it retaliatory strikes against US targets.

The tragedy killed 176 people, mostly Iranians and Canadians.

State television showed buses packed with people arriving at the mosque hours before Khamenei's sermon, walking over US and Israel flags on their way.

Police were out in force ahead of the prayers as they have been since several days of protests erupted over the downing of the airliner, AFP correspondents reported.

Authorities have called for rallies across Iran after the prayers.

They are intended to be a show of support for Iran's armed forces and Revolutionary Guards.

- Better governance -

Canadian Foreign Minister Francois-Philippe Champagne vowed Thursday to push Iran for answers about the tragedy.

Prime Minister Justin Trudeau has previously said US President Donald Trump's policies contributed to the heightened tensions that led to the catastrophe.

In June 2019, Iran and the United States had also appeared to be on the brink of direct military confrontation after Tehran shot down a US drone it said had violated its airspace.

Trump said he called off retaliatory strikes at the last minute.

The animosity between Washington and Tehran has increased since Trump unilaterally withdrew from a landmark nuclear deal in 2018 and reimposed biting sanctions.

In Iran, the air disaster sparked public outrage and anti-government demonstrations took place every day from Saturday to Wednesday.

Concentrated in the capital, the protests appeared smaller than a nationwide wave of demonstrations in November prompted by a fuel price hike. At least 300 people died in a crackdown after those demonstrations, according to Amnesty International.

Rouhani implicitly acknowledged a crisis of confidence in authorities, but called Wednesday for "national unity", better governance and greater pluralism.

On Thursday, Rouhani also defended the policy of openness that he has pursued since his first election in 2013, and which Iran's ultra-conservatives criticise.

"Of course, it's difficult," he acknowledged, but added, "the people elected us to lower tensions and animosity" between the Islamic republic and the world.