Economic sanctions against Iran are beginning to bite, and hard. The country’s currency has fallen more than 40 percent since Sept. 24. Skyrocketing inflation is destroying incomes and eating at savings.

This summer brought a wave of strikes and last week riots broke out after the regime shut down black-market foreign-exchange dealers. Some protesters shouted, “We don’t want nuclear energy!”

This week European Union foreign ministers are scheduled to discuss ways to make the sanctions even tougher. On the agenda: a ban on Iran’s natural gas exports and stiffer curbs on transactions with the country’s central bank.

Washington should encourage these efforts and press for even tougher measures, while urging countries that still buy Iranian oil — such as India, Japan and China — to further cut back purchases. Iranian oil exports have dropped by half this year, cutting oil revenue by $5 billion a month.

The regime says it’s staying the course and if current talks fail Iran will press even harder to enrich uranium. But rising unrest and discontent may force other choices. The situation already is sparking internal spats. Ali Larijani, parliament speaker, publicly placed the blame for most of the economic problems with the government of President Mahmoud Ahmadinejad, whose term ends next summer.

The United States and European Union should block the Iranian central bank’s access to currency reserves in offshore banks.

More steps could include sanctions that bar dealings with other Iranian financial entities, measures to prevent international insurers from covering Iran-bound cargoes other than food or medicine, and a ban on transactions with any entity linked to the energy sector.

The recent riots show that such measures can significantly reduce the mullahs’ shrinking support. That will steadily raise the political costs of Iran’s refusal to permit international inspections and cause more in the regime to question the wisdom of proceeding with its nuclear program.