Exxon Mobil and Chevron CEOs warned Friday that gasoline and diesel refineries are already working at full capacity and can’t be increased to meet global shortages due to the Iran war and other geopolitical conflicts. They suggested that might raise gas costs in the coming months.

Exxon Mobil CEO Darren Woods revealed that the corporation will “push as hard as we can” to boost fuel output due to the impact of rising energy prices on consumers’ wallets. He noted on the company’s results call that supply out has lowered capacity to a level I’ve never seen. “It’s going to take a while for the industry to kind of climb its way out of that hole.”

Their comments come as the Trump administration rushes to mitigate the effects of rising fuel prices with three months until the election. The American Automobile Association estimated national pump prices at $4.10 per gallon, up nearly a dollar from last year. The U.S. Energy Information Administration reported this week that US refineries operated at 97 percent of their operable capacity this month, while Shell reported Friday that it was running its refineries at record rates above their official capacities in the second quarter.