On Sunday night, the new package of US sanctions on Iran entered into force after Tehran proved its non-compliance with the nuclear agreement in 2015, as well as its subversive policies towards the Middle East.
Sky News Arabia is trying to provide a simple guide to understanding the sanctions imposed by the Bush administration on November 5 and those previously imposed.
What sanctions have come into force?
US sanctions, which entered into force on Monday, aim to hit the heart of Iran's economic system: oil exports.
All business with Iranian oil companies will be banned as the United States appears determined to deliver Iranian oil exports to zero, with oil sales accounting for about 80 percent of Iran's gross national income.
The current sanctions on Iran's financial sector will be tightened from Monday morning onwards, and all financial transactions will be blocked with the Iranian central bank and a number of other banks.
The US decision means that all foreign countries, entities or companies, with minor exceptions, are prevented from entering the US market if they decide to proceed with the purchase of Iranian oil or continue to deal with Iranian banks.
What sanctions have been imposed before?
When the United States pulled out of the Iranian nuclear deal on May 8, it gave its partners a time limit to work with Iran.
The deadline for the first 60 days was August 6, at which point Iran was barred from trading in the US dollar. Sanctions were also imposed on major Iranian industries such as automobile and carpet production.
The United States has also completely banned the sale of commercial aircraft or spare parts to Iran.
What is the purpose of the sanctions?
According to the Trump administration, the sanctions represent Tehran's "maximum pressure" to force Iranian leaders to "change course."
On May 21, Foreign Secretary Mike Pompeo presented a list of 12 requests the United States said must be met in exchange for lifting sanctions, including Tehran's suspension of its missile program and ending support for terrorist groups in the Middle East.
In addition, Pompeo said that "Iran must withdraw all forces under its command from Syria, and the demobilization of Shiite militias in Iraq."
Regime change is not among the declared objectives of US sanctions, but public statements by National Security Adviser John Bolton suggest that this would be welcome from Washington.
What is the impact of sanctions so far?
The Iranian riyal has been in a state of free fall for months, losing 70 percent of its value this year, with an unprecedented rise in inflation.
Since last June, Iran's oil exports have fallen by about a third, and high energy costs have been linked to the population's standard of living, leading to mass demonstrations in several Iranian regions over the past year.
Many international companies have been forced out of Iran since May, including European companies that fear they will be removed from the US market, the most lucrative, if they stay in Tehran.
Imports to Iran have been severely hampered in all areas. Important drugs, for example, are difficult to find and are very expensive if they exist.
