South Korea's trade surplus topped 2.38 billion U.S. dollars in the first 20 days of April with fall in imports exceeding export drops, the nation's customs officials said Tuesday.

Exports stepped down 16.5 percent on-year to 19.92 billion U.S. dollars, while imports plummeted 39.7 percent to 15.54 billion U.S. dollars, according to the Korea Customs Service.

The trade account for the same period a year earlier hit a deficit of 4.31 billion U.S. dollars.

South Korea had marked a 13-month consecutive trade surplus before falling into a deficit territory in last January with shortfalls of 3.63 billion U.S. dollars.

The trade account made a turnaround in February to hit a surplus of 2.9 billion U.S. dollars, and hit a record monthly high of 4.28 billion U.S. dollars in March.

The nation is expected to register a trade surplus of 14.7 billion U.S. dollars during the second quarter with imports likely to stay contracted, according to the Korea International Trade Association (KITA).