TEHRAN, Iran -- Iranian President Hassan Rouhani said Tuesday his country is in a "fight" with the U.S., a day after protesters angered by Iran's tanking economy confronted police in front of parliament. In a televised speech, Rouhani blamed the U.S. for Iran's woes and said the U.S. is trying to damage the country by creating "an economic war."

"The U.S. cannot defeat our nation, our enemies are not able to get us to their knees," he said.

Rouhani's comments came after protesters angered by Iran's tanking economy confronted police in front of parliament Monday. It was the first such confrontation since similar demonstrations rocked the country at the start of the year. The demonstration signaled widespread unease in the wake of President Donald Trump's decision to withdraw the U.S. from Iran's nuclear deal with other world powers and restore sanctions on the country.

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It wasn't immediately clear who led Monday's protests. Iran's semi-official news agencies, Fars, ISNA and Tasnim, described the protests at the Grand Bazaar as erupting after the Iranian rial dropped to 90,000 to the dollar on the country's black market, despite government attempts to control the currency rate. Videos posted to social media showed protesters at the bazaar heckling shopkeepers who refused to close.

A short time later, a little over a mile from the Grand Bazaar, videos shared by Iranians on social media appeared to show a crowd confronting police at parliament. Iran's semi-official ISNA news agency reported Tuesday that authorities detained many of the protesters.

Iranian protesters shout slogans during a demonstration in central Tehran on June 25, 2018. Atta Kenare/AFP/Getty Images

Prosecutor Abbas Jafari Dolatabadi said the "main provocateurs" who planned the protest and threatened shopkeepers to close their stores were arrested. He did not elaborate on the number of people detained.

Still, ISNA reported the country's parliament speaker, Ali Larijani, said Tuesday that the Rouhani administration hasn't done enough to confront the economic problems.

CBS News State Department reporter Kylie Atwood reports that this marks a revival of protests seen in December and January.

At the end of last year, similar economic protests roiled Iran and spread to some 75 cities and towns, becoming the largest demonstrations in the country since its 2009 disputed presidential election. A crackdown on the protests in late December and early January saw at least 25 people killed and nearly 5,000 arrested.

Iran has announced a list of 15 demands for improving relations with the United States, including a U.S. return to the 2015 nuclear accord, in response to a similar list of demands made by Washington last month.

In May, U.S. Secretary of State Mike Pompeo called for a wholesale change in Iran's military and regional policies, threatening the "strongest sanctions in history" if it refused. The U.S. withdrew from the landmark nuclear agreement with world powers earlier that month.

The nuclear deal, however, still stands, CBS News' Atwood reports. While the U.S. is out, other countries remain committed to the deal. The U.K., France, Germany, China and Russia are trying to hold onto the deal because they say it's the only way to control Iran's nuclear capability.