U.S. economic pressure on Iran is intended to turn Iranians against their government, Supreme Leader Ayatollah Ali Khamenei was quoted as saying on Saturday by his website.
The country's rial currency has lost up to 40 per cent of its value since last month, when U.S. President Donald Trump pulled out of Iran's 2015 nuclear accord and said he would reimpose sanctions and try to curb Iranian oil exports.
"They bring to bear economic pressure to separate the nation from the system ... but six U.S. presidents before him tried this and had to give up," Khamenei was quoted as saying by Khamenei.ir, referring to Trump.
Speaking to graduating Revolutionary Guards officers, Khamenei accused the United States and Sunni Muslim Gulf Arab states that regard Shia Muslim Iran as their main regional foe of trying to destabilise the government in Tehran.
"If America was able to act against Iran, it would not need to form coalitions with notorious and reactionary states in the region and ask their help in fomenting unrest and instability (in Iran)," Khamenei said in remarks carried by state TV.
Khamenei was speaking after three days of protests in Tehran and other cities in which hundreds of traders in the bazaar closed their shops to voice anger at the rial's plunge. Such merchants have mostly been loyal to the leadership since the 1979 Islamic Revolution overthrew the monarchy.
Some of the graduating Guards officers had drawn the flag of Israel, Iran's arch-enemy, on the soles of their boots, pictures from the military ceremony carried by semi-official news agency Tasnim showed.
State news agency IRNA reported that top government officials including President Hassan Rouhani and the heads of parliament and the judiciary had met to discuss the prospective U.S. sanctions.
"Various scenarios of threats to the Iranian economy by the U.S. government were examined and appropriate measures were taken to prepare for any probable U.S. sanctions, and to prevent their negative impact," IRNA said.
Measures to achieve self-reliance in gasoline production were among issues discussed, IRNA said.
The United States has told allies to cut all imports of Iranian oil from November and is unlikely to offer exemptions, a senior State Department official said on Tuesday as the Trump administration seeks to cut off funding to Iran.