TEHRAN -- Everyone in Iran's capital, from government officials to business people, was waiting anxiously on Friday to hear what action President Trump would announce against the Islamic Republic, reports CBS News correspondent Elizabeth Palmer.

Already the currency has fallen in anticipation of aggressive moves by the White House.

Iran's President Hassan Rouhani has said that if Mr. Trump tries to pull out of -- or override -- the 2015 nuclear deal, he would damage U.S. credibility in doing so, and end up isolated.

The speaker of Iran's parliament said on Friday that any U.S. move against the nuclear deal would be an "insult" to the United Nations which, he said, would allow Iran to decide its own response.

Speaker Ali Larijani said he hoped Russia -- a signatory to the nuclear pact -- would intervene to keep the deal intact.

In Moscow, Russian President Vladimir Putin's spokesman Dmitry Peskov told journalists on Friday that if the U.S. abandons the agreement, it "could seriously aggravate the situation around the Iranian nuclear dossier."

"Such actions will unequivocally damage the atmosphere of predictability, security, stability and non-proliferation in the entire world," Peskov said.

The powerful Iranian Revolutionary Guard Corps, meanwhile, knowing they're expected to be targeted in some way, have been sounding outright threatening.

The head of the Guard, Gen. Mohammad Ali Jafari, said this week that if new sanctions are enacted against the force, the U.S. should move all its military assets back more than 1,000 miles from Iran's borders. In other words, out of Iran's missile range.

But Palmer says behind all the rhetoric, there is real dismay. Iran, with a large, educated population and very high unemployment, needs foreign investment.

Whatever measures the White House announces today, they are bound to scare most of that money away, which will hurt.