MOSCOW, May 8 (Xinhua) -- Russia's trade surplus rose 26.6 percent year on year to 48.5 billion U.S. dollars in the first quarter, the Federal Customs Service said in a statement Tuesday.

Russia's exports increased by 23.1 percent in the first three months to 103.5 billion dollars, while imports grew by 20.3 percent to 55 billion, it said.

Russian exports are traditionally based on fuel and energy products, which accounted for 64.5 percent of the total in the first quarter, compared with 64.7 percent in January-March 2017.

The value of exported fuel and energy products rose by 22.8 percent and the tonnages by 4 percent.

Metals, the second largest export item, accounted for 11 percent of the total in the first three months, compared with 9.9 percent in the same period last year.

The value of the metals exports increased by 37.3 percent and the volume by 11.2 percent.

Other major export items were chemical products and machinery and equipment.