The United States on Tuesday slapped sanctions on foreign entities and individuals who evade the U.S. sanctions against Iran and Syria, in an effort to tighten the pressure on the two countries.

According to an executive order signed by U.S. President Barack Obama on Tuesday, the Treasury Department targeted foreign individuals and entities that have violated the U.S. sanctions against Iran or Syria, or that have "facilitated deceptive transactions" for persons subject to such sanctions, the department said in a statement.

"With this new authority, Treasury now has the capability to publicly identify foreign individuals and entities that have engaged in these evasive and deceptive activities, and generally bar access to the U.S. financial and commercial systems," said the statement.

The decision imposed "serious consequences" on foreign persons who seek to evade the U.S. sanctions and undermine efforts to pressure Iran and Syria, said Under Secretary for Terrorism and Financial Intelligence David Cohen in the same statement.

"Whoever tries to evade our sanctions does so at the expense of the people of Syria and Iran, and they will be held accountable," he warned.

According to the Treasury Department, U.S. persons will be prohibited from engaging in transactions with a designated " foreign sanctions evader," which means "effectively cutting the evader off from the U.S. marketplace."

The U.S. government has slapped a series of sanctions on Iran and Syria. It has targeted Iran's central bank and oil exports for expanded sanctions in its continued efforts to press Tehran to stop its uranium enrichment activities.