DUBAI/WASHINGTON: Iran said on August 21 that it would respond "crushingly" to any new U.S. threats after Washington said it planned to impose the toughest financial penalties in history in an effort to topple the Iranian leadership.

The United States was preparing new sanctions that U.S. Treasury Secretary Scott Bessent said he would explain on August 24. President Donald Trump had earlier warned that any country providing "any type of lifeline to Iran" could face economic consequences.

Iran's Armed Forces Chief of Staff, Major General Ali Abdollahi, said Iran's response would be broad and decisive.

Abdollahi said Iran's armed forces were prepared across land, sea, air, air defense and cyberspace and would respond to any new threats with crushing, punishing and devastating force, Iranian media reported.

Iran's parliament speaker, Mohammad Baqer Qalibaf, the country's main negotiator in mediated talks with the United States, said Washington appeared to have realized it could not win a direct military confrontation.

Speaking in neighboring Iraq, Qalibaf said Iran needed to make plans to deal with what he called unfair sanctions and overcome them. He accused the United States and Israel of using economic and "cognitive" warfare.

Oil prices fell slightly on August 21 but were still on track for a second straight weekly increase. Prices had risen on Thursday after the United States announced its new sanctions threat.

Bessent told CNBC that he was unsure why oil prices had risen because maximum economic pressure would probably mean there would not be a large-scale return to military action.

The United States and Iran announced two ceasefire agreements in April and June, aimed at restoring the free movement of ships through the Strait of Hormuz and moving toward an end to the nearly six-month-old conflict. Both ceasefires, however, quickly collapsed.

Bessent said Washington intended to bring down the Iranian government and that it was time for U.S. allies and other countries to decide where they stood. He described the naval blockade imposed again on Iran in July and the planned toughest-ever sanctions as a "one-two punch".

Iran has faced almost continuous economic sanctions for nearly 50 years, since the 1979 Islamic Revolution. The country is now dealing with high inflation, a weakening currency, energy shortages and damaged infrastructure.

Some Iranians interviewed by Reuters said additional economic pressure could make life even harder, weaken the country's clerical leadership and trigger unrest. However, there has been no sign of such unrest since a deadly crackdown on protests in January.

Before Bessent's comments, Iran's Foreign Ministry said U.S. sanctions would not create any hesitation among Iranians in protecting the country's independence, dignity and national sovereignty.

Iranian President Masoud Pezeshkian, who is considered relatively moderate and has raised concerns about the economy, said Iran would respond to any attack with crushing force. However, he also said the war should now end because the United States was internationally isolated, repeating his earlier position.

Bessent said China gets half of its energy from the Middle East and argued that Beijing should cooperate with Washington's approach.

China bought more than 80 percent of Iran's exported oil in 2025, according to data from analytics firm Kpler. However, further U.S. economic pressure on China could lead to retaliation, especially as Beijing has recently eased some restrictions on exports of its important rare-earth minerals.

Trade sources told Reuters that offers of Iranian crude to Chinese buyers had already fallen since the United States reimposed its blockade on Iranian ports in mid-July.

China's embassy in Washington said sanctions and pressure would not help solve the problem and called for a diplomatic solution.