A Couple Danced in Tehran’s Streets. Now They Are in Prison.

A young Iranian couple appears alone in the video, dancing in front of the Azadi Tower in downtown Tehran. They smile as they move together. The woman’s uncovered hair trails behind her as he lifts her into the air.

The video was posted online in early November, weeks after the death of 22-year-old Mahsa Amini at the hands of the police sparked widespread protests in Iran. In the months since, those protests have grown stronger, as the government has arrested thousands and conducted a campaign of public executions.

Now the couple — Astiyazh Haghighi, 21, and Amir Mohammad Ahmadi, 22 — have each been sentenced to five years in prison, according to Mizan, a news agency overseen by the country’s judiciary, on charges including “colluding against national security,” and “propaganda against the establishment.”

The agency said the couple used their Instagram accounts “to call for people to participate in the ‘riots,’ ” a reference to the protests, and said the police arrested the couple on Nov. 1, after they ignored warnings to curb their “malicious activity” online.

The couple’s Instagram accounts have nearly one million followers each. On Ms. Haghighi’s Instagram account, she describes herself as a blogger. Her photos show a young woman passionate about her relationship and fashion. She appears in loosefitting clothing. Her bleach-blond hair is variously shown only partially covered — with a bandanna, hat or occasionally a hood.

The video, which was uploaded at the height of the demonstrations, struck a nerve among Iranians, attracting views on multiple social media platforms. It also caught the attention of the Iranian police, who were working to quash the demonstrations. The video was taken down at some point, but has been since reposted by other social media users.

In one post on her Instagram account, published during the first week of the demonstrations, Ms. Haghighi wrote about the pressure she had come under from the government, and recounted several encounters she had with the morality police on the streets of Tehran.

“They put me into the van. I will never forget the fear — I was trembling,” she wrote, describing her abduction by the authorities. “But this was nothing compared to the stress I feel every day when I receive their anonymous calls.”

Ms. Haghighi and Mr. Ahmadi were both beaten as they were arrested at their homes, according to HRANA, an Iranian human rights news agency, citing sources close to the defendants. Their cases were accelerated by the Revolutionary Court system, with no defense lawyers present, HRANA said in its report.

The verdict was handed down by Abolghassem Salavati, a Revolutionary Court judge with a reputation for imposing harsh punishments, according to Skylar Thompson, who heads advocacy for Human Rights Activists in Iran. She said Ms. Haghighi was being held at Qarchak, a notorious and isolated women’s detention facility southeast of the capital. Mr. Ahmadi was detained at Evin prison, she said.

Their arrests were the “latest display of Iran’s ill-functioning judiciary” and another example of “how consequential a system lacking complete due process can be — and has been for many years,” Ms. Thompson said. The group has estimated that 763 Iranians who participated in the demonstrations have been tried and convicted so far.

The “sheer number of those run through the judicial system in such a short time,” Ms. Thomson said, is indicative of a system that is deeply flawed, operating in “complete violation of international standards.”