TEHRAN, Iran (CNN) -- Iranian riot police swarmed a major bazaar Wednesday in Tehran as demonstrators launched protests against firebrand President Mahmoud Ahmadinejad, blaming him for plummeting currency that's leaving families across the country struggling.
A day after Ahmadinejad acknowledged that his country is taking a hit, and placed the blame largely on "the enemy's" sanctions, crowds of protesters also took to the streets in another commercial area in the capital, shopkeepers said.
They chanted slogans slamming Ahmadinejad's regime and complained about the high prices of goods and food. Riot police dispersed the crowd, a shopkeeper said.
The country's supreme leader Ayatollah Ali Khamenei echoed Ahmadinejad's position Wednesday, saying that growing pressures are mainly aimed at making his country surrender, "but the Iranian nation has and will never surrender to pressures and this has made the enemy furious," the semi-official FARS news agency reported.
The United States and European Union have imposed numerous sanctions aimed at pressuring Tehran into sitting down for international negotiations on its nuclear program. Earlier this week, U.S. State Department spokeswoman Victoria Nuland said the falling value of the rial comes as "firms all over the world are refusing to do business with Iranian companies."
She cited "the most punishing sanctions we have ever been able to amass as an international community," calling them, "very important for trying to get Iran's attention on the important denuclearization work."
The rial's value was cut in half from September of last year through last month, the Congressional Research Service said in a report. It has fallen even further since, including a sharp nosedive this week, reaching historic lows against the value of the dollar.
At the main bazaar in central Tehran, some protesters used boxes and tires to start fires, according to a merchant who spoke on condition of anonymity for security reasons.
But the semi-official Mehr news agency quoted the head of the bazaar's merchant's association as saying that officials had observed "suspicious" activity and identified people around the market who were from "outside the bazaar community."
The bazaar was closed for safety reasons, Mehr reported.
Dozens of police on motorcycles responded to the scene, and dozens more were on foot.
Police also gathered in two major squares -- Ferdosi and Vali Asr -- although no demonstrations were immediately reported in those spots.
In a speech Wednesday, Ahmadinejad also said part of the problem plaguing the country's currency is "internal."
He blamed "22 ringleaders" who the country's intelligence services have determined are causing tensions and manipulating currency.
The president gave no details. But people who trade currency illegally have been increasingly concerned about a crackdown by Iranian forces.
Months ago, an Iranian man told CNN that with the country's economic downfall, the only way for his sons to live a decent life was to fall in with influential people or make shady business deals -- such as trading foreign currency on the black market.
But Ahmadinejad focused the majority of his remarks on the United States and the West.
"There is a hidden war, a very pervasive and heavy warfare that is happening across the world directed towards Iran," he said.
Ahmadinejad insisted the sanctions hurt the people, not the government.
The "enemy" has "succeeded in reducing the sale of our oil to an extent, but God willing, we will fill it up," he insisted.
The country's economy "has become a tool for psychological warfare," the president said.
The price of a popular bread called barbari has gone from about 1,000 rials each to about 5,000 rials amid the increasing sanctions. A local baker told CNN the cost will likely skyrocket further. The wheat used to make the bread is imported.
Feta cheese cost 50,000 rials per kilogram in March. The price has since tripled. Meat that cost up to 190,000 rials per kilogram then has doubled in price.
Analysts say the crippling sanctions are aimed at getting the regime to blink and compromise in nuclear talks.
"Sanctions are a form of economic warfare," Mark Dubowitz, with the Foundation for Defense of Democracies, told CNN.
"They are designed to put sufficient pressure on the average Iranian," which could help trigger an uprising against the government -- or at least cause leaders to fear one, he explained.
Though some sanctions against Iran have existed for decades, the most recent ones have had a stronger impact.
"We've seen only 10 months of what I would call significant and severe economic pressure," Dubowitz said.
But there's no evidence the sanctions have compelled the Iranian government to change its nuclear stance, analysts say.
Ahmadinejad, in his speech Wednesday, denied suggestions that the measures could work.
"They lie when they say sanctions are pressure on the government," he insisted, adding that sanctions "are always a pressure on nations" -- meaning average citizens.
"It's a rock that the enemy has thrown. So what we should do? We should pick up the rock and throw it at them."
Anthony H. Cordesman, national security analyst at the Center for Strategic and International Studies, said sanctions must be "large scale and consistent" over time to be effective.
It's not possible to predict whether sanctions will change the regime, Cordesman said. "This is a duel and you find out just how effective you are over time."
Trita Parsi, founder and president of the National Iranian American Council, said so far there is no sign of a shift in the government's nuclear program.
"If Iran were a democracy, you would have had a situation in which there would have been far greater protests," he said. "Any democratic government would have fallen by now."
Parsi said he was skeptical that large-scale protests are in the cards.
Iranians "are not going to go out there and risk their lives for a change if they don't know what the next thing is," he said.
Iran saw a widespread popular uprising in 2009 after Ahamdinejad's contested re-election, triggering a brutal, deadly crackdown by government forces -- and Ahmadinejad held onto power.
CNN's Shirzad Bozorgmehr reported from Tehran; CNN's Josh Levs reported from Atlanta. CNN's Reza Sayah also contributed to this report.