China warned Tuesday that the US decision to impose sanctions on buyers of Iranian oil will "intensify turmoil" in the Middle East and in the international energy market.

The White House announced Monday it was calling an end to six-month waivers that had exempted several countries -- including major importer China -- from unilateral US sanctions on Iranian oil exports.

"China firmly opposes the US implementation of unilateral sanctions and its so-called long-armed jurisdiction," foreign ministry spokesman Geng Shuang said at a regular press briefing.

"The relevant move by the United States will intensify the turmoil in the Middle East and the turmoil in the international energy market."

In seeking to reduce Iran's oil exports to zero, the Trump administration is targeting the country's top revenue earner in its latest no-holds-barred move to crush the economy and scale back the clerical regime's influence.