Crude oil prices rose modestly Monday after Iran ruled out talks to extend the memorandum of understanding it signed with the U.S. on June 17, as the 60-day window for a broader nuclear agreement expired. U.S. crude oil futures gained 0.76% to $83.03 per barrel and Brent crude rose 0.92% to $89.33 per barrel. The arrangement was supposed to keep the Strait of Hormuz (a vital oil shipping lane) open while negotiations continued over Tehran's nuclear program, but Iran's Foreign Ministry spokesman Esmaeil Baqaei said the U.S. had violated the understanding from the start and dismissed the relevance of the deadline; a senior Iranian official also told Reuters that Tehran would shift to offense rather than rely on defense if diplomacy fails.