Oil prices ticked higher on Monday after Iran refused to negotiate an extension of its memorandum of understanding with the United States. A senior Iranian official told Reuters that if diplomatic efforts with Washington fail, Tehran will shift from a defensive posture to offensive action.

US crude futures rose 0.76% to $83.03 per barrel, while international benchmark Brent crude gained 0.92% to $89.33 per barrel. The two-month negotiation window, established by the memorandum signed on June 17, officially expired on Monday, with the pact having guaranteed safe passage through the Strait of Hormuz during that period.

The memorandum had set a 60-day timeline for both sides to negotiate a final agreement on Iran's nuclear program. However, according to Iran's Tasnim News Agency, Foreign Ministry spokesman Esmail Baghaei explicitly rejected any talks to extend the agreement. "We have not initiated any substantive negotiations at all. The US violated this understanding from the very beginning, so this 60-day period has lost its practical significance," Baghaei told Tasnim.