Saipan's cheapest petrol blew past the psychological barrier of $5 US dollars in the Northern Marianas on Tuesday night.
Mobil Oil Marianas' regular unleaded petrol shot up to $5 dollars 6 cents a gallon.
Shell Marianas was expected to follow suit last night.
The 15-cent increase on Tuesday night means that Saipan motorists are now paying 35 cents more than what they used to pay at the start of the year because of three rounds of prices changes since January.
CNMI petrol prices are the highest in the United States, where prices averaged $3.47 a gallon on Tuesday, as well as among U.S. territories.