"The real legal and moral question is why civilian infrastructure is being targeted at all," said one expert.

After US President Donald Trump made his genocidal declaration on Tuesday that the "whole civilization" of Iran "will die tonight," reports began to roll in of people across the country standing outside the power plants, bridges, and other civilian infrastructure the president promised to bomb.

Photos shared to social media by the government-affiliated Mehr news agency showed scene after scene of Iranians forming human chains outside power plants in Tabriz and Kermanshah.

A video showed dozens of students assembled on the Dezful bridge in southwestern Iran, which is more than 1,700 years old and is believed to be one of the oldest functioning bridges in the world.

Over the weekend, Trump said that unless Iran opened the Strait of Hormuz, a critical shipping lane that it has used as a chokepoint against the Western economy, by Tuesday, he would bomb infrastructure relied upon by tens of millions of Iranians, which Amnesty International said could amount to a "war crime."

"We’re giving them till tomorrow, eight o’clock eastern time, and after that, they’re going to have no bridges. They’re going to have no power plants," Trump said on Monday, reiterating his plans to bomb Iran "back to the Stone Ages."

According to Iranian President Masoud Pezeshkian, more than 14 million people in the country responded to the threat by volunteering to put their bodies on the line and defend the infrastructure at risk. He said they'd "declared their readiness to sacrifice their lives in defense of Iran.”

The government has encouraged Iranians, including children and young students, to take to the streets to form human chains around infrastructure that may come under threat, leading some Western media outlets to raise the fear that people were being used as "human shields."

Sina Toossi, a fellow at the Center for International Policy, however, said this "is a deeply misleading framing."

"Iranians are not being placed in front of targets," he said, referencing several videos of the demonstrations. "Many are voluntarily showing up to defend the infrastructure that keeps their society alive."

He noted the participation of Iranian celebrities in the human chains, including the composer and Tar player Ali Ghamsari, who stationed himself outside a power plant, and the pop singer Benyamin Bahadori, who filmed a video of himself walking along a bridge that had come under threat.

"This is about people trying to safeguard electricity, water, and basic civilization under open threat," Toossi said. "The real legal and moral question is why civilian infrastructure is being targeted at all."

Agnès Callamard, secretary general of Amnesty International, said on Tuesday that Trump's threats could prove "apocalyptic" to millions of Iranians, plunging the "entire country into darkness and depriv[ing] millions of their fundamental human rights to life, water, food, healthcare, and an adequate standard of living."

"Power plants, water systems, and energy infrastructure are indispensable to civilian life, underpinning access to clean water, medical care, hospital electricity, food supply chains, and basic livelihoods," she added. "Attacking them would be disproportionate and thus unlawful under international humanitarian law and could amount to a war crime.”