The price of Brent crude gained around 2% this week as a result of Iran's threat to end compliance with the nuclear deal and worries over inadequate global supply due to U.S. sanctions on Iran and Venezuela.
The international benchmark was trading at $70.98 a barrel at 1130 GMT on Friday for a 2.03% weekly gain after ending the previous week at $69.48 per barrel.
American benchmark West Texas Intermediate (WTI) was at $62 a barrel at the same time, posting little change for only a 0.1% increase, after closing Friday at $61.94 per barrel.
Oil prices started the week with gains on Monday, with Brent rising 2.53% and WTI adding 0.5%, due to worries that U.S.' sanctions on Venezuela and Iran would continue to lower crude production and exports from those countries.
However, U.S. President Donald Trump's announcement Sunday of his plan to raise tariffs on $200 billion worth Chinese goods to 25% from 10% escalated the trade tension between the world's two largest economies.
The souring negotiations have signaled once again that global oil demand could be lower than estimates this year unless a new deal is made. Brent plummeted 1.91% on Tuesday, while WTI was down 1.37%.
On Wednesday, crude prices regained from their Tuesday losses after Iranian President Hassan Rouhani said Wednesday that Tehran would end its compliance with the 2015 nuclear deal if European partners to the agreement do not begin to take action to protect Iran against U.S. sanctions.
Tehran also has recently threatened to close the Strait of Hormuz, the world's largest chokepoint of oil shipments, after Washington began to re-impose sanctions.
Iran's threat to end its compliance with the historic nuclear deal could raise tensions in the Middle East and threaten secure oil supply from the region.
After Iran's announcement, Brent gained 0.7% on Wednesday, while WTI rose 1.17%.
The U.S.' tariff rate hike came into effect at 0400 GMT on Friday, and Trump reiterated his tough stance against China via his social media account.
"Talks with China continue in a very congenial manner - there is absolutely no need to rush," Trump wrote on Twitter, and added "China should not renegotiate deals with the U.S. at the last minute."
If trade talks fail, or a deal is not reached, global economic growth could be hurt, as well as overall demand, which could put a downward pressure on oil prices.
By Ovunc Kutlu and Gulsen Cagatay