Oil futures edged up on Wednesday as Iran suspended cooperation with the U.N. nuclear watchdog but a surprise build in U.S. crude supplies limited gains. Brent crude was up 39 cents, or 0.6%, to $67.50 a barrel at 10:44 a.

U.S. and global oil benchmark prices opened up 4% Sunday evening, underscoring the concerns about what the conflict means for the world’s oil supplies.