The people of Iran face a sensitive time because of the pressure from America and economic problems, Supreme Leader Ayatollah Ali Khamenei said in a key address broadcast by state television on Thursday.

Khamenei was speaking to tens of thousands of members of the Basij militia and top Revolutionary Guards leaders gathered in a stadium in Tehran.

Discord between Iran and the United States has worsened since U.S. President Donald Trump withdrew from a multilateral nuclear deal with the Islamic Republic in May and reimposed sanctions.

"The situation of the nation, region and world is sensitive, especially for us the people of Iran," Khamenei said.

"Sensitive in this respect that on one hand we have the shouting of the arrogant powers and politicians of imperialist America...on another hand the economic problems of the nation and the tightness of the livelihood of a large portion of the weak people in the country."

The Iranian rial has lost approximately 75 percent of its value since the beginning of 2018.

The United States has said it plans to impose new sanctions targeting Iran's oil sector on Nov. 4 with the aim of stopping Iran's involvement in conflicts in Syria and Iraq and bring the Islamic Republic to the negotiating table for its ballistic missile program.

Iranian officials have said they are involved in the Syrian conflict at the request of President Bashar al-Assad and have refused any negotiations on their missile program.

At a press briefing in Geneva on Thursday, Robert Wood, the U.S. Ambassador to the Conference on Disarmament, said: "We want to see Iran no longer operating in Syria ... And we will continue to tighten sanctions on Iran – you will be seeing some new steps in November, and we’ll go from there."

In his speech in Tehran, Khamenei also said that Iran must deliver a slap to America by defeating sanctions.

"With the kindness of God we will defeat sanctions and the defeat of sanctions is the defeat of America," Khamenei said. "And America must receive another slap from the people of Iran with the defeat of sanctions."