Iran's grip on the Strait of Hormuz is throttling the world's energy supplies and inflicting global economic pain, but the struggles of the Islamic Republic's own economy are testing its ability to withstand the war and defy Washington's demands.

Iranians have been hit by spiralling prices for food, medicine and other goods. At the same time, the country has seen mass job losses and business closures caused by strike damage to key industries and the government's monthslong shutdown of the Internet.

The economic cost of the war and the US naval blockade "has been very substantial and unprecedented for Iran", said Hadi Kahalzadeh, an Iranian economist and research fellow at Brandeis University.