Oil extended its slump on concerns over a brusing global trade war and OPEC+ plans to revive halted production.

Brent retreated toward $70 a barrel after Beijing immediately retaliated against Donald Trump’s tariffs. US levies on imports from Canada and Mexico also came into effect.

Futures started tumbling on Monday after OPEC+ announced output increases in April, and touched the lowest price in five months on Tuesday.

Global oil markets were set for a supply surplus this year even if OPEC+ kept output flat, the International Energy Agency said in a report last month. The cartel, led by Saudi Arabia and Russia, plans to increase production by 138,000 barrels a day next month, according to a statement posted on its website.

“While the increment is indeed small, and can be suspended according to market conditions, the bottom line is that it is still an increase amidst signs of higher production within the producer group,” said Harry Tchilinguirian, group head of research at Onyx Capital Group.

Already this year some producers have been lifting output. Kazakhstan’s production hit a record, and there’s the looming risk of returning barrels from the Kurdistan region of Iraq.

Crude has trended lower since mid-January on concerns about lackluster demand and the fallout from President Trump’s trade policies and his stance toward the war in Ukraine. Levies on Chinese exports were doubled to 20%, while most of what the US imports from Canada and Mexico is subject to a 25% duty.

Canadian energy such as crude is subject to a 10% tariff.