U.S. and global oil futures declined on Thursday as a hefty rise in last week’s U.S. supplies and uncertainty surrounding tariff disputes helped to weaken the outlook for crude demand, prompting prices to settle at their lowest levels of the year.

Thanks to abundant supply and fairly flat demand, oil prices are forecast to fall — unless tariffs and geopolitics get in the way.

Oil prices finished with daily gains on Friday after new sanctions were imposed on Iran's crude exports but prices were down for the week as investors worried about U.S. President Donald Trump's renewed trade war on China and threats of tariffs on other countries.

Oil futures on Wednesday marked their lowest settlement prices of the year, after official U.S. data showed a weekly climb of nearly 9 million barrels in U.S. crude inventories and as the U.S.-China trade battle threatened to dent demand.

Oil prices were on course for a third-straightly weekly fall on Friday as President Donald Trump's new tariff policies leave markets uncertain.