TEHRAN, Iran – Iranian authorities used aggressive measures Wednesday in an attempt to halt the nosedive of the country’s currency, making arrests, vowing to stamp out sidewalk money changers and warning merchants against fueling the mounting public anger over the economy.

There were unconfirmed reports of sporadic violence. Associated Press photos showed riot police blocking a street with the charred hulks of a garbage can and a motorcycle that had been set on fire. Smoke was rising from the area in central Tehran near the main bazaar.

The sweeping responses to the freefall of the rial – which has lost more than a third of its value in a week – underscored the worries for Iranian leaders after months of dismissing the West’s economic squeeze seeking to rein in Tehran’s nuclear program.