(Bloomberg) – Oil prices will surge if the Israel-Hamas war escalates to include Iran, according to shale magnate Scott Sheffield.

The founder and Chief Executive Officer of Pioneer Natural Resources Co. issued the warning during an interview with Bloomberg Television on Wednesday, just hours after ExxonMobil Corp. agreed to buy the shale giant for $59.5 billion.

The 71-year-old executive was joined by Exxon CEO Darren Woods, who said the fate of the crude market hinges on the fundamentals of supply and demand.

“It’s really going to be a function of demand, and any loss in supply that’s out there today is going to have a big impact,” Woods said. “As long as that market says tight, we’re gonna see more volatility and higher prices.”

Benchmark U.S. crude futures dropped below $85 a bbl on Wednesday as the conflict remained largely confined to Israel and Gaza. Iran is OPEC’s fourth-largest oil supplier, behind Saudi Arabia, Iraq and the United Arab Emirates.