American motorists could soon pay more at the pump amid spiking oil prices due to the U.S.-Israel attacks on Iran, with experts predicting gasoline prices could rise sharply this week.

U.S. President Donald Trump on Monday threatened to escalate the war with Iran if it blocked oil shipments from the Middle East, even as he predicted ​a quick end to the conflict.

The deliberations reflect White House worries that the surge in oil prices ‌following more than a week of U.S. and Israeli strikes on Iran will hurt U.S. businesses and consumers ahead of the November...