Premium gasoline now sells for $3.27 a gallon.
On Guam, Mobil regular gas now retails for $2.84 per gallon, up from $2.69 per gallon.
The move came even as oil prices in the international market fell below $37 a barrel on Tuesday.
Motorists were caught off-guard by the sudden gasoline price hike.
The price of gasoline rose to as much as $5 a gallon last year when the crude oil prices reached $147 a barrel.
Some motorists expressed concern that the price hike will result in higher electric bills.
The Commonwealth Utilities Corp. adopted in 2006 a billing formula that allows it to charge customers the actual price of fuel it imports to run its machines that produce power and water throughout the CNMI.
Shell stations are also expected to increase its fuel prices.
Mobil earlier said that the global market dictates its prices in the region.
The oil firm said gasoline prices in the CNMI, which are relatively higher compared to Guam and the U.S., are affected by the changes in the world market price of crude oil; government regulations and taxes; the regional gasoline supply and demand balance; transportation costs; local distribution and marketing costs.
