At least 10 people have been killed during protests that have spread across Iran, including two members of the country's Basij paramilitary force.
Tension was growing as authorities warned demonstrators they would not allow economic grievances to spiral into unrest.
The deaths were reported in several western provinces, where clashes between protesters and security forces have been most intense, state media and human rights groups said.
The demonstrations, sparked by soaring inflation, a plunging currency and rising living costs, are smaller than previous waves of unrest but have spread nationwide, including to Tehran.
On Friday, Iran’s police issued a warning, saying the force would support lawful protests but respond firmly to violence. “We will not allow civil protests to be turned into insecurity and chaos,” police spokesman Brigadier General Saeed Montazerolmahdi was quoted by state media as saying.
He added that recent gatherings were “entirely economic and civil” in nature, driven by demands for improved living conditions, but accused “foreign-guided elements” of attempting to hijack demonstrations.
Iran’s security and intelligence agencies said they had detained several people accused of "links to foreign-based opposition groups" and of trying to incite unrest under the cover of protests.
President Masoud Pezeshkian on Thursday pledged to crack down on corruption and rent-seeking, while urging restraint and national unity. His remarks struck a more conciliatory tone than that adopted by his predecessors during previous waves of unrest.
The situation took on an international dimension after US President Donald Trump threatened intervention if Iranian authorities violently suppressed protesters. “If Iran shoots and violently kills peaceful protesters, which is their custom, the United States of America will come to their rescue,” he wrote on social media.
Iranian officials swiftly cited the remarks as evidence of foreign interference. Parliament Speaker Mohammad Bagher Ghalibaf warned that any US action would provoke retaliation. “All American bases and forces in the entire region will be our legitimate target in response to any potential adventure,” he said.
The unrest began on Sunday when shopkeepers in Tehran closed their businesses in protest against the sharp fall of the rial. Students later joined demonstrations at around 10 universities, including several in the capital. Tension escalated on Wednesday after a government building in southern Iran was attacked, prompting the country’s chief prosecutor to warn of a “decisive response” to any attempt to undermine security.
Iran’s economy has been under sustained pressure from US and international sanctions linked to its nuclear programme. The rial lost more than a third of its value against the dollar last year, while official data shows annual inflation exceeded 50 per cent in December.
Although the current protests are less extensive than those sparked by the 2022 death of Mahsa Amini in police custody, analysts say they reflect deep-rooted economic frustration, compounded by the aftermath of last year’s war with Israel and US strikes that hit key nuclear facilities.
