Crude futures pulled back on Friday, giving up gains from the previous session as trade concerns weighed on the market and fueled concerns about demand.

U.S. West Texas Intermediate (WTI) crude futures finished Friday's session down 47 cents at $68.49 per barrel. Brent crude futures fell 31 cents to $73.14 per barrel at 2:25 p.m. ET.

WTI also posted its fifth straight weekly loss. Brent is on track for its fourth week of declines in five, set for a drop of more than 1 percent.

"It's a jittery feel here, as long as we have Iranian sanctions uncertainty and tariff uncertainty, and it doesn't take much to spark a significant swing one way or the other," said Jim Ritterbusch, an analyst in Galena, Illinois.

Fears that Chinese demand could taper fueled the pullback on Friday after state oil major Sinopec cut its purchases of U.S. crude. China's Unipec, the trading arm of Sinopec, has suspended crude oil imports from the United States due to the growing trade spat between Washington and Beijing, three sources familiar with the situation said on Friday.