The spreading unrest, sparked by economic protests by Tehran shopkeepers, adds to a list of pressures on the regime.

Protesters angry over Iran's ailing economy conducted a sit-in Tuesday at Tehran's Grand Bazaar, witnesses said, with security forces ultimately firing tear gas and dispersing demonstrators as the rest of the market shut down.

Tehran also increasingly cut back its cooperation with the International Atomic Energy Agency, the U.N.'s nuclear watchdog, as tensions increased over its nuclear program in recent years. The IAEA’s director-general has warned Iran could build as many as 10 nuclear bombs, should it decide to weaponize its program.

Nine days of anti-government protests engulf Iran as Trump warns of consequences. Iranian-Americans praise president's support for demonstrators.

Demonstrations over economic pain shift to provincial cities and towns in growing challenge to Islamic republic’s leaders

Iran shifts from import subsidies to direct $7 monthly payments for citizens as the currency loses its value and protests intensify nationwide, according to reports.

The payments are the latest step to alleviate economic pressures, but given the severity of the crisis, critics say, they are likely to do little.

Reza Pahlavi, the exiled son of the last shah of Iran, thanked President Donald Trump for his "support" of Iranian protesters.