Chevron (CVX.US) Chief Executive Mike Wirth said on Tuesday that banning diesel exports from the United States could push up prices in some parts of the country and create problems for other nations that rely on American supply.

Speaking at the Energy Intelligence Forum in London, Wirth said, "You could see some upward price pressure in parts of the United States. And I think it would send a very bad signal, especially to our allies, because the United States has always been a reliable supplier in times of crisis."

Late last week, after the Group of Seven and its partners agreed to release some emergency fuel reserves to curb soaring oil prices, US President Donald Trump said he would not ban US diesel exports. Trump's statement means he has dropped his previously considered stance of restricting diesel exports, temporarily eliminating a major supply risk facing the global refined fuel market.

The coordinated release of reserves comes as the global diesel market faces one of its worst supply crunches in recent years. According to Kpler data, before the Middle East conflict broke out, the Middle East accounted for about 19% of global diesel exports, North America about 15%, and Russia about 11%. But due to disruptions to Middle East energy shipments and declines in Russian refining and exports, two major sources that originally accounted for nearly one-third of global supply have contracted at the same time.

Wirth also said that after the Persian Gulf war ends, oil and gas demand will continue to grow, and his company may join a consortium for an oil pipeline from Iraq to the Mediterranean. Wirth said that with technological advances, Chevron can now drill more wells with fewer rigs than before.