The US is expected to announce on Monday that buyers of Iranian oil need to end imports soon or face sanctions, a source familiar with the situation told Reuters, triggering jump in crude prices to their highest for 2019 so far.

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

U.S. President Donald Trump 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.