WASHINGTON/SINGAPORE (Reuters) – The United States is expected to announce on Monday that all buyers of Iranian oil will have to end their imports shortly or face sanctions, a source familiar with the situation told Reuters, triggering a 3 percent rise in crude prices.

The source confirmed a report by a Washington Post columnist that the administration will terminate the sanctions waivers it granted to some importers of Iranian oil late last year.

Benchmark Brent crude oil futures rose by as much as 3.2 percent to $74.30 a barrel, the highest since Nov. 1, in early trading on Monday in reaction to expectations of tightening supply. U.S. West Texas Intermediate (WTI) futures climbed as much as 2.9 percent to $65.87 a barrel, its highest since Oct. 30. [O/R]

U.S. President Donald Trump has made clear to his national security team over the last few weeks that he wants to end the waivers to exert “maximum economic pressure” on Iran by cutting off its oil exports and reducing its main revenue source to zero.

In November, the U.S. reimposed sanctions on exports of Iranian oil after President Trump unilaterally pulled out of a 2015 nuclear accord between Iran and six world powers.

Washington, however, granted waivers to Iran’s eight main buyers – China, India, Japan, South Korea, Taiwan, Turkey, Italy and Greece – that allowed them limited purchases for six months.

On Monday, Secretary of State Mike Pompeo will announce “that, as of May 2, the State Department will no longer grant sanctions waivers to any country that is currently importing Iranian crude or condensate,” the Post’s columnist Josh Rogin said in his report, citing two State Department officials that he did not name.

On April 17, Frank Fannon, U.S. Assistant Secretary of State for Energy Resources, repeated the administration’s position that “our goal is to get to zero Iranian exports as quickly as possible.”

Peter Kiernan, lead energy analyst at the Economist Intelligence Unit (EIU) said “a severe loss in (Iranian) volumes will put pressure on the supply side, given the political uncertainty currently blighting other oil exporters, such as Venezuela and Libya.”

Global oil markets have also tightened this year because of supply cuts led by the Organization of the Petroleum Exporting Countries (OPEC).

As a result, Brent prices have risen by more than a third this year, and WTI more than 40 percent over the same period.

Kiernan said he expected the “Trump administration to try to rely on Saudi Arabia … to reverse policy and increase volumes to calm market fears of oil supplies quickly tightening.”

Saudi Arabia is the world’s biggest exporter of crude oil and OPEC’s de-facto leader.

“If there is a time for the U.S. to be able to take a hard line it is now, with the Saudis having over 2 million barrels (per day) of spare capacity,” said Tony Nunan, oil risk manager at Mitsubishi Corp in Tokyo.

(GRAPHIC: Iran crude oil & condensate shipping departures – tmsnrt.rs/2IBQF06)

ASIA HIT HARDEST

An end to the exemptions would hit Asian buyers the hardest. Iran’s biggest oil customers are China and India, who have both been lobbying for extensions to sanction waivers.

South Korea, a close U.S. ally, is a major buyer of Iranian condensate, an ultra-light form of crude oil that its refining industry relies on to produce petrochemicals.

Government officials there declined to comment as well, but Kim Jae-kyung of the Korean Energy Economics Institute said the end of the sanction waivers “will be a problem if South Korea can’t bring in cheap Iranian condensate (for) South Korean petrochemical makers.”

Japan is another close U.S. ally in Asia that is also a traditionally significant buyer of Iranian oil.

Takayuki Nogami, chief economist at Japan Oil, Gas and Metals National Corporation (JOGMEC) said the end of the sanction waivers “is not a good policy for Trump.”

Nogami said he expected oil prices to rise further because of the U.S. sanctions and OPEC-led supply cuts.

So far in April, Iranian exports were averaging below 1 million barrels per day (bpd), according to Refinitiv Eikon data and two other companies that track exports and declined to be identified.

That is lower than at least 1.1 million bpd estimated for March, and down from more than 2.5 million bpd before the renewed sanctions were announced last May.