WASHINGTON — Three of eight importers granted waivers by Washington to buy oil from Iran have now cut their shipments to zero, a US official said on Tuesday, adding that improved global oil market conditions would help reduce Iranian crude exports further.

The United States reimposed sanctions on Iran after President Donald Trump last May withdrew the country from a 2015 nuclear deal between Iran and several world powers, accusing it of supporting terrorism and conflicts in Syria and Yemen.

“In November, we granted eight oil waivers to avoid a spike in the price of oil. I can confirm today three of those importers are now at zero,” Brian Hook, the special US envoy for Iran, told reporters.

Hook said US oil sanctions against Iran had removed about 1.5 million barrels of Iranian oil exports from the market since May 2018.“This has denied the regime access to well over $10 billion in (oil) revenue — a loss of at least $30 million a day,” he said.

Hook did not identify the three.

“There are better market conditions for us to accelerate our path to zero,” Hook said. “We are not looking to grant any waivers or exceptions to our sanctions regime.”

A senior Trump administration official told reporters on Monday that the US government was considering additional sanctions against Iran that would target areas of its economy that have not been hit before.

Hook said more than 26 rounds of US sanctions against Iran had restricted the country’s cash flow and constrained its ability to operate in the region.

Earlier on Tuesday, U.S. Secretary of State Mike Pompeo blamed Iran’s government of mismanagement that has led to devastating flooding across the country. At least 47 people have been killed in the past two weeks from flash floods. — Reuters