ABC News anchor David Muir and his team have traveled to Iran for a special Inside Iran report from the streets of Tehran, revealing the effects of Washington's tightening sanctions on the country.

We landed in Iran, a country where U.S. journalists are rarely allowed in. Even rarer, we got access to the people on the streets of Tehran.

It is a tenuous time in Tehran, a bustling city of 12 million. Below ground is a gleaming subway system - far quieter and cleaner than the famous subways of New York City.

There is also something very different: The back of the train is "reserved for women" in this Islamic Republic. Women wear head scarves and their dress is enforced by the moral police.

Above ground, the streets bustle with traffic.

Beyond the trains and the traffic, something else is on the move: prices. There is skyrocketing inflation. Some of the cars lined up bumper-to-bumper have tripled in price, one driver says.

Tehran has been squeezed by ever-tightening economic sanctions, led by the United States, in an attempt to force the country to prove its nuclear program is for non-military purposes and to allow increased U.N. inspections to affirm that the Iranian government is not pursuing a nuclear weapon.

Due to sanctions, Iran's currency - the rial - has lost 80 percent of its value in the last year, causing the prices of imported goods to soar.

Groceries and increasingly scarce medicine have all felt the impact of a currency in freefall.

The leadership in Iran remains publicly defiant, telling the Iranian people that they will not negotiate under pressure, despite the measurable impact of the sanctions.

"The U.S. is pointing a gun at Iran and wants us to talk to them," said Iran's Supreme Leader Ayatollah Ali Khamenei to air force commanders in Tehran earlier this month. "The Iranian nation will not be intimidated by these actions."

The comments were made in response to new American financial restrictions that went into effect Feb. 6, prohibiting purchases of Iranian oil using currencies or precious metals and forcing prospective buyers to use a barter system, trading oil for goods.

Iran will return to the nuclear negotiating table with the United States and others Feb. 26 in Almaty, Kazakhstan, for the first time since talks collapsed eight months ago.