Iran's currency value slumped further against foreign currency in the street market of Tehran on Monday as 1 U.S. dollar was exchanged for about 21,700 rials, compared to 19,200 rials 10 days ago.

Meanwhile, 1 euro was traded for 26,900 rials on Monday, while the number was around 24,000 rials on July 27.

The current Iranian rial's value is the lowest since the beginning of the new Iranian year, which started on March 20.

On Monday, the value of U.S. dollar in Theran's street market demonstrated 9,440 rials difference with the official rate of U.S. dollar which stood at 12,260 rials.

The slump followed U.S. President Barack Obama's last Tuesday announcement of additional sanctions against Iran's energy and petrochemical sectors over the Islamic republic's disputed nuclear program.

Obama said he ordered the latest round of sanctions to "deter Iran from establishing payment mechanisms to circumvent existing sanctions."

The Iranian currency came under heavy pressure in January after the U.S. sanctions on Iran's central bank was announced.