Monday's action brings to more than 900 the number of Iranian entities sanctioned by the Trump administration in almost two years.
"President Trump's predecessors also began crafting their Iran policy with similar bravado; but came around to accepting and respecting the reality of Iran as they became more experienced in office". "But as is the case with all coercive policies, follow-through matters, especially when the Iranians are bragging that they will "proudly" bust sanctions", he said in an analysis Monday. Iranian state television aired footage of air defense systems and anti-aircraft batteries in two-day military maneuvers underway across a vast stretch of the country's north.
Iran, they say, has been subjected to energy-sector sanctions so often over the past three decades that it has developed highly refined techniques to sell bootleg oil and launder the profits - despite Western efforts to stop such activities.
South Korean refiners have reduced their oil imports from Iran since the USA pulled out of the Joint Comprehensive Plan of Action, a nuclear deal with Iran, in May.
Eight countries who have significantly curtailed their imports of Iranian oil have been granted temporary waivers to allow them to continue importing Iranian oil after the penalties take effect.
"Today the enemy [the US] is targeting our economy... the main target of sanctions is our people", Iranian President Hassan Rouhani said.
Mr Pompeo said more than 20 countries had already cut their oil imports from Iran. Worldwide, 4,500 oil tankers carry 2 billion barrels of crude per year over nearly 140 million square miles of ocean, according to industry and intelligence agency estimates.
Switzerland said it was holding talks with the United States and Iran about launching a humanitarian payment channel to help food and drugs keep flowing to Tehran.
"We have the toughest sanctions ever imposed".
Makers of 'vile video' mocking Grenfell Tower may be prosecuted
In a statement, London's Metropolitan Police Service called the video "vile" and urged people with information to come forward. A spokesman added: "We are disgusted and shocked at the inhumanity and callousness of those involved in this video".
Iran's exports peaked at 2.8 million barrels per day (BPD) in April, including 300,000 barrels per day of condensate, a lighter form of oil that when underground tends to exists as gas. "Enforcement from the U.S. could do a lot to change minds".
The move intensifies a campaign by Trump to force Iran to further limit its nuclear work and halt a missile program, as well as end its support for proxy forces in Yemen, Syria, Lebanon and other parts of the Middle East.
Analysts said expectations of an economic slowdown in coming months were weighing on the fuel demand outlook, while concerns eased on the supply-side after Washington granted sanction waivers to eight importers of Iranian oil that will allow them to continue purchases.
The United States reintroduced sanctions against Iranian oil on Monday while giving some of Washington's closest allies exemptions that allow Tehran's biggest customers, mostly in Asia, to keep buying crude for now. "We are prepared to resist any pressure", Rouhani said.
"All eyes will be on Iranian exports, whether there will be some cheating around USA sanctions, and on how quickly production will fall", said Riccardo Fabiani, an analyst for Energy Aspects.
The new American sanctions particularly hurt Iran's vital oil industry, a crucial source of hard currency for its anemic economy.
Support from Iran and Russian Federation has allowed the regime of dictator Bashar al-Assad to remain in power.
"Of course, we welcome these developments". If Iran fails to do this, he said, it would "continue down the path toward economic disaster". This [decision] has become a result of our tough negotiations with United States officials over the last six months.