In a letter to House Speaker John Boehner, R-Ohio, the president said evasion is cutting into the effectiveness of sanctions imposed by previous executive orders going back to 1994.
"I have determined that efforts by foreign persons to engage in activities intended to evade U.S. economic and financial sanctions with respect to Iran and Syria undermine our efforts to address the national emergencies described above," Obama said. "To address this situation, the order takes additional steps with respect to those national emergencies."
Individuals identified by the treasury secretary would be barred from doing business in or with the United States and from entering the country, the president said.
"The foreign sanctions evaders [executive order] provides treasury additional means to impose serious consequences on foreign persons who seek to evade our sanctions and undermine international efforts to bring pressure to bear on the Iranian and Syrian regimes. Whoever tries to evade our sanctions does so at the expense of the people of Syria and Iran, and they will be held accountable," said Under Secretary for Terrorism and Financial Intelligence David S. Cohen.
The tightened sanctions would also help Americans from unwittingly trading with foreign individuals or groups in violation of said sanctions, a release from the U.S. Department of the Treasury said.