Cambodia has imported 871,000 tons of petroleum in the first six months of the year, a 5.6 percent decline compared with the 922,800 tons at the same period last year, the figures of the Ministry of Commerce showed Monday. During the January-June period this year, the country spent about 825 million U.S. dollars to buy petroleum, down 10 percent from 921 million U.S. dollars it paid over the same period last year, the figures said. A liter of premium gasoline goes for 1.35 U.S. dollars in Phnom Penh on Monday. The Southeast Asia nation entirely purchases oil and gas from Vietnam, Singapore and Thailand as its seabed\'s oil and gas have not been exploited. The country is planning to build a 5-million-ton oil refinery under the investment of Chinese companies including China Development Bank, China Export and Credit Insurance Corporation and China Perfect Machinery Industry Corporation. The oil refinery project, which is estimated to cost 1.67 billion U.S. dollars, will be built on the 80-hectare area within the boundary of Preah Sihanouk province and Kampot province in Cambodia. Cambodia\'s oil demand last year was 1.65 million tons. It is estimated that the demand will jump to 3 or 4 million tons a year in coming years.