Tehran's interim Friday prayers leader, Ayatollah Ahmad Jannati, called on theIranian nation and the government to form a united front against what he called an " economic war" waged on the Islamic republic by the West, Press TV reported on Friday.

"This is a war in which the enemy, which has suffered defeat in other wars, is trying to regain its lost face through victory," Jannati, also chairman of Iran's high legislative body, i.e. Guardian Council, was quoted as saying.

He said economic problems in Iran have their root in politics, adding that theUnited Statesseeks to restore its domination on the region by inflicting an economic defeat on Iran.

Jannati added that economic problems in the Islamic republic will not continue and are limited to a short period, and urged the Iranian nation to resist the West's economic pressure, according to semi-official Fars news agency.

Iran's currency value slumped against foreign currency in the street market of Tehran on Thursday as 1 U.S. dollar was exchanged for about 20,260 rials, compared to 19,200 rials one week ago.

Meanwhile, 1 euro was traded for 24,800 rials Thursday, while the number was 23,850 rials last week.

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

The new depreciation in the Iranian currency rate came as U.S. PresidentBarack Obamaannounced on Tuesday 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 U.S. Congress on Wednesday passed additional sanctions seeking to further stifle Iran's oil exports, just one day after Obama announced new sanction measures to pressure the Islamic republic.

The House of Representatives voted 421-6 for the new penalties, while the Senate passed them unanimously later. The legislation will land on Obama's desk for his signature.

House Foreign Affairs Committee chairwoman Ileana Ros-Lehtinen said the new sanctions, the toughest ever imposed on Iran, seek to "tighten the chokehold on the regime beyond anything that has been done before."

She told the House that the measures will ultimately deprive Iran of "hard currency and funds needed to sustain its nuclear program." Oil export is the lifeline of the republic's economy.

The new measures, among others, target any individual or entity that works with Iran's petroleum or natural gas sector, engages in mining of uranium with the country, sells oil tankers to Tehran, or provides insurance to the National Iranian Tanker Co.

According to media reports, sinceEuropean Unionsanctions, which ban the purchase and transport of Iranian oil, started one month ago and continued to the present time, Iran's oil exports have fallen more than 50 percent to 1.2 million barrels a day and it has lost an estimated 133 million U.S. dollars in oil sales per day.