ISTANBUL — Iran’s nearly week-long protests, sparked by economic despair but quickly widening into demands for broad change, have turned deadly, with multiple human rights groups saying that several people had been killed by security forces.

President Donald Trump issued a warning to Iran on social media on Friday, writing that if Iran “violently kills peaceful protesters, which is their custom, the United States of America will come to their rescue. We are locked and loaded and ready to go.” The White House did not respond to a request for comment on what kind of aid Trump was referring to.

The Center for Human Rights in Iran had tallied six killings by Friday, according to spokeswoman Bahar Ghandehari, while the Abdorrahman Boroumand Center for Human Rights in Iran said in an email Friday that it had documented the killings of eight people during the protests thus far.

Arina Moradi, a spokeswoman for the Hengaw Organization for Human Rights,said that 10 people have been killed so far, including a 15-year-old. Those reported killed were all men, mostly in their 20s and 30s.

The Human Rights Activists News Agency, which follows Iran closely, said on Thursday that 119 Iranians had been arrested, seven killed, and at least 33 injured. It said protests had occurred in at least 32 cities across Iran.

Iranian authorities have acknowledged only one death thus far, Amirhesam Khodayarifard, who they claim was a member of the Basij militia force deployed to suppress unrest. A judiciary official in Lorestan province, where Khodayarifard was killed, said the government would “identify the perpetrators of this incident and deal with them in accordance with the law.”

But Hengaw said Khodayarifard was a protester and authorities were pressuring his family to declare that their son was a member of the Basij, including by making the return of his body contingent on such a claim.

The Abdorrahman Boroumand Center said the family had been under intense pressure to endorse the government narrative. The center shared a video on Friday showing a cleric visiting with the family and referring to Khodayarifard as a martyr and Basij member. The authorities refer to people killed in the course of defending the government or for its approved causes as “martyrs.”

The center also said government officials had tried to hold a state-sponsored funeral for Khodayarifard on Friday but a crowd of people “reclaimed the body from the authorities and tore down state-installed banners.” It said Khodayarifard’s father later publicly said his son was not a member of the Basij. Video published by Persian-language news outlets outside Iran showed a chaotic scene at the funeral, with crowds appearing to chase uniformed men.

The Tasnim news agency, affiliated with Iran’s Islamic Revolutionary Guard Corps, said that “rioters” had shouted obscenities and thrown stones at the funeral. The outlet referred to Khodayarifard as a “martyr.”

Fars News, also IRGC-affiliated, reported that two people had been killed in the city of Lordegan during unrest there. The Tabnak news site, which is affiliated with a senior Iranian official, said three people had been killed in Azna, in western Lorestan province during an attack on a police station.

Rights groups reported the killing of a 37-year-old man, Dariush Ansari, in Fouladshahr, near the major city of Isfahan. Authorities also appeared to dispute the circumstances of that death, with Mehr News, a semiofficial outlet, reporting that he had died of injuries sustained during a fight in front of his house and that investigations into his “murder” had commenced.

The deaths were mostly clustered in Lordegan in southwest Iran and two cities in Lorestan province.

The Washington Post could not independently verify the circumstances of the killings or reports of government pressure on Khodayarifard’s family. Family members of people killed by state forces are often put under immense pressure by the government not to publicize the circumstances of their loved ones’ deaths or speak to reporters, making it difficult for journalists to verify claims.

Some videos have shown security forces shooting toward demonstrators, and such actions fit a documented pattern from past rounds of protest in Iran, especially in recent years. At least 321 Iranians were killed by security forces during mass protests in November 2019, according to Amnesty International. A U.N. fact-finding mission found that authorities had carried out “unnecessary and disproportionate use of lethal force” in response to protests in 2022 that were sparked by the killing of a woman in police custody.

Trump’s social media post pledging support for Iranian protesters immediately put a spotlight on events inside the country. Past American presidents have sometimes been hesitant to wade into overseas protests, wary of committing U.S. involvement and unsure of how to navigate another country’s domestic politics.

President Barack Obama in 2009 and 2010 offered limited support for the Green Movement protest movement in Iran. Obama has subsequently said he regretted not going further.

“Every time we see a flash, a glimmer of hope, of people longing for freedom, I think we have to point it out,” he said in 2022 on “Pod Save America,” a liberal podcast hosted by his former aides.

It was unclear what Trump meant by his “locked and loaded” remarks. Even with the U.S. military reorienting much of its combat power toward Venezuela in recent months, thousands of U.S. troops remain in the Middle East and land-based fighter jets are stationed in several countries.

Pentagon spokesman Sean Parnell said the Defense Department “stands ready to execute” the president’s orders “at any time and in any place.”

Another U.S. official with knowledge of operations in the region said there were no immediate changes to U.S. military posture in the Middle East following Trump’s remarks. The official spoke on the condition of anonymity because of the sensitivity of the issue.

Iranian authorities’ response to the protests runs counter to the rhetoric of Iranian President Masoud Pezeshkian, who has said the protesters have legitimate demands and told reporters on Thursday that “if people are unhappy with us, we are the ones at fault.”

The most recent protests started Sunday with shopkeepers in Iran whose businesses have been wrecked by the sharp depreciation of the Iranian rial in recent weeks. The demonstrations then spread throughout Tehran and to cities across the country and drew in other elements of Iranian society, including university students.

Though the protests started with economic grievances, chants heard in videos showed protesters voicing more fundamental demands, as well as praise for Iran’s deposed monarchy.

Dan Diamond and Dan Lamothe in Washington contributed to this report.