Japan's trade surplus in January dropped 42.8 percent from a year earlier, the first decline in 11 months, as an increase in oil imports exceeded export growth, the Finance Ministry said Monday in a preliminary report.

Imports of crude oil and petroleum products increased due to a jump in oil prices amid mounting worries over a war in Iraq and the suspension of Tokyo Electric Power Co.'s nuclear plants, ministry officials said.

The customs-cleared trade surplus for January -- exports minus imports -- came to 105 billion yen.

Exports rose 7.9 percent year-on-year to 3.84 trillion yen, backed by overseas demand of automobiles and electronics components, including semiconductors. It marked the 10th consecutive month of increase, but the amount fell sharply from December, affected by manufacturers' New Year's holiday, officials said.

Imports grew 10.7 percent in January from the previous year to 3.74 trillion yen, the fifth consecutive month of rise.

By region, the merchandise trade with other parts of Asia marked a deficit of 25.4 billion yen, but the deficit fell 44.9 percent from the figure marked a year earlier.

Exports from Asia stood at 1.63 trillion yen, up 15.4 percent from last year, marking the 11th consecutive month of rise. Imports from the region stood 1.66 trillion yen, up 13.5 percent year-on-year, marking the fifth consecutive month of growth.

Imports from China, registering 722.77 billion yen in January, have exceeded that from the United States and marked the largest import amount for six months in a row.

Japan's surplus with the U.S. in January fell 8.9 percent from a year before to 476.1 billion yen, the first decline in five months.

The surplus with the European Union jumped 160.1 percent to 158.6 billion yen. , marking the second consecutive month of increase.

The yen averaged 119.73 against the dollar in January, compared with 131.00 a year earlier.