California, Mar 5 (IANS): The average price of a gallon of self-serve regular fuel in San Diego County topped $5 for the first time, while the overall cost in Southern California also reached a new record-high.

The gas price in the region, containing 10 counties including Los Angeles, Orange, Ventura, Riverside and San Bernardino among others with about 24 million residents, witnessed the biggest daily increase on Thursday night since July 13, 2015, rising over 12 cents on average, reports Xinhua news agency.

The price hike in San Diego County on Friday occurred after pump rate in those counties broke records on Thursday.

Fuel costs in the region are about 31 cents higher than last week and nearly 42 cents more than a month ago, according to the American Automobile Association (AAA).

In Los Angeles County, the most populous in the US, average price rose 13.8 cents to $5.152 on Friday.

The AAA's latest data also showed that in California, the average gas price on Friday reached $5.074, passing $5 for the first time and breaking record highs for the state.

Prices in California have long been among the highs in the country, and they have soared in recent years in part because of changes at some West Coast refineries.

The state regulators require a boutique, cleaner-burning grade of gasoline and diesel that are not easily blended and few refiners outside the state can make.

State gas taxes and fees also contribute to California's fuel price cost.

Oil industry analysts attribute the price spike to the possibility of a supply shortage because traders, shippers, insurance companies and banks are avoiding Russian oil transactions for fear of running afoul of Western sanctions.

According to NBC 7 channel, Russia was the third-largest source of oil products sold in the US last year, behind only Mexico and Canada, and responsible for 8 per cent of all imports.

Russia is also the country' second-largest supplier of platinum, a metal used to build exhausts for automobiles.