President Obama on Monday imposed additional sanctions on Iran, issuing an executive order that punishes financial institutions who make large transactions using Iranian currency and delivers a blow to the country’s automotive industry.

“The steps taken today are part of President Obama’s commitment to prevent Iran from acquiring a nuclear weapon, by raising the cost of Iran’s defiance of the international community,” White House Press Secretary Jay Carney said. “Iran must understand that time is not unlimited. If the Iranian government continues down its current path, there should be no doubt that the United States and our partners will continue to impose increasing consequences.”

Under the executive order, the United States will target “foreign financial institutions that knowingly conduct or facilitate significant transactions for the purchase or sale of the Iranian rial, or that maintain significant accounts outside Iran denominated in the Iranian rial.” The White House said the order marked the first time the rial had been targeted directly.

As for Iran’s auto industry, sanctions will be imposed on the “sale, supply, or transfer to Iran of significant goods or services" used to build cars and trucks.

Critics accuse Obama of not doing enough to deter Iran’s nuclear capabilities. The White House counters that a series of sanctions have left Iran more isolated than at any point in recent history.

The White House said it is open to reaching a diplomatic solution with Iran but that such a window is closing quickly.