The average price of a gallon of gas in California already stands at more than $6, but more uncertainty looms as the last oil tanker from the Middle East arrived in the Golden state this week.

The Los Angeles Times reported on Sunday that the New Corolla, which left the Middle East for California before the war broke out, is delivering about 2m barrels of crude oil from Iraq to Long Beach. It was the last planned shipment to pass through the strait of Hormuz.

The California Energy Commission vice-chair, Siva Gunda, told legislators on Tuesday that the state can meet fuel demand for the next six weeks with its current supply.

California has the highest gas prices in the US. It imports about a third of its oil from the Gulf, and the state will now have to find new sources to replace it. Compared with other states, California imports significantly more of its oil supply from abroad.

While oil prices have risen in recent weeks, the current supply has not yet been severely affected as markets have continued to receive oil that was already in transit when the conflict began.

“The war in Iran and the closing of the strait of Hormuz has actually been buffered by the fact that all of these tankers were at sea at the time that the strait of Hormuz closed,” Michael Ross, a professor at the University of California, Los Angeles, told ABC7.

“So all of that supply has still been making its way to consumers. This is the last shipment of that supply that was keeping prices relatively stable. So that should worry us.”

The US-Israeli war with Iran has significantly disrupted the global oil market and driven up gas prices around the world. The American Automobile Association reported the national average had reached $4.54 on Tuesday while in California the average price was $6.16. Prices are at their highest level in nearly four years.

The price of gas is frequently a major source of debate in California politics, including during Tuesday’s gubernatorial debate. Democratic candidates largely pinned the blame for the most recent surge in costs to Donald Trump’s war in Iran, while the Republican Steve Hilton challenged those arguments, instead pointing to California’s regulations.

Gavin Newsom, California’s governor, has sharply criticized Trump over the rising prices.

“An inconvenient truth for MAGA: gas prices have risen MORE nationwide than they have in California since the start of the war,” Newsom said. “No plan. No exit strategy. And Americans are paying the price – every day.”

On Wednesday, stock markets surged and oil prices fell after Donald Trump said that if Iran agreed to a deal with Washington, the war would end and the strait of Hormuz would be “open to all”.

Meanwhile, economic data shows that the rising fuel prices have hit low-income Americans the hardest. Americans with lower incomes dropped their gas consumption after the Iran war began and still spent more at the pump, according to a report from the Federal Reserve Bank of New York.