[HOUSTON] Oil prices were mostly steady on Friday, ending the week slightly lower as trade tensions stoked by a US move to hike tariffs on Chinese goods overshadowed tightened global supplies and expectations of rising US refining demand.

Brent crude oil settled 23 cents, or 0.4 per cent, higher at US$70.62 a barrel, but posted a weekly loss of 0.3 per cent.

U.S. West Texas Intermediate (WTI) crude futures ended 4 cents lower at US$61.66, with a weekly loss of 0.5 per cent.

After a volatile week, investors were worried over the possibility of a protracted and bitter US-China trade war, despite last-minute efforts to salvage a deal.

US President Donald Trump on Friday said he was in no hurry to sign a trade deal with China as Washington imposed a new set of tariffs on Chinese goods and negotiators ended a second day of talks.

Growing trade tensions between the world's two largest oil consumers could affect oil demand. The United States and China together accounted for 34 per cent of global oil consumption in the first quarter of 2019, data from the International Energy Agency showed.

Prices gained some support on Friday as investors anticipated US Gulf Coast and Midwestern refineries, which are coming out of seasonal maintenance, to boost oil demand ahead of the US summer driving season.

"Crude oil has more potential for upside," said Tom Kloza, chief oil analyst at the Oil Price Information Service. "With Gulf refineries starting up, demand is going to be significantly above supply for the next 100 days or so."

Investors also focused on tightened supplies following Opec-led production cuts since the start of the year. Investors believe the Organization of Petroleum Exporting Countries (Opec) and its producer allies will extend the six-month output-cut agreement in coming weeks.

"We're waiting to see whether the Saudis signal their extension of the production cut," in coming weeks, said Gene McGillian, vice president of market research at Tradition Energy in Stamford, Connecticut. "The market is finding its next driver."

Markets have been buoyed further by Washington's bid to cut Iran's oil exports to zero. The United States reimposed sanctions on Iran in November after pulling out of a 2015 nuclear accord between Tehran and world powers last year.

It initially allowed Iran's biggest buyers to continue purchasing oil via waivers for another six months, but those exemptions ended at the beginning of May.

China Petrochemical Corp (Sinopec Group) and China National Petroleum Corp (CNPC), the country's top state-owned refiners, are skipping Iranian oil purchases for loading in May after Washington ended sanction waivers to turn up pressure on Tehran, three people with knowledge of the matter said.

REUTERS