Vice President JD Vance was set to travel to Switzerland to continue into the next phase of negotiations with Iran. Vance’s trip has been postponed while Israel has opened up more strikes on Lebanon. Photo by Aaron Schwartz/UPI | License Photo

June 19 (UPI) -- Global oil prices have fluctuated slightly on Friday, briefly reaching back above the $80 per barrel mark for Brent crude, as the United States and Iran called off further talks in Switzerland.

A stall in talks between the United States and Iran have cast doubt over the preliminary peace agreement reached earlier this week. The oil market has begun reflecting that uncertainty early Friday.

Vice President JD Vance was set to travel to Switzerland to continue into the next phase of negotiations with Iran. Vance's trip has been postponed while Israel has opened up more strikes on Lebanon.

Part of the agreement between the United States and Iran included an end to military operations in Lebanon.