Iran, which has sparred with the West over its nuclear program, is again threatening to block a critical Persian Gulf shipping route in response to a European embargo of Iranian oil. Action by Iran would certainly increase the risk for violence in the region, slowing tanker traffic.
More than a third of the world's seaborne oil is shipped out of the Persian Gulf.
Benchmark U.S. crude added $2.97, about 3.5 percent, to $86.72 per barrel in New York.
Meanwhile, gas prices ticked a little higher overnight. Tuesday's increase, the first increase in 77 days. Experts say pump prices will range between $3.30 and $3.50 through Labor Day.