US West Texas Intermediate crude was at $100.88 a barrel, down 53 cents, or 0.52% Oil prices slipped on Monday after US President Donald Trump waived sanctions and tariffs on ​Russia that may lead to more Russian fuel exports. Brent ​crude futures fell $1.43, or 1.30%, to $108.43 a barrel by 2340 ‌GMT after settling at its highest since May 19 on Friday. US West Texas Intermediate crude was at $100.88 a barrel, down 53 cents, or 0.52%.