South Korea's exports gained 3.7 percent from a year earlier in April, marking a third consecutive month of increase, while outbound shipments to the United States dropped sharply on the Donald Trump administration's hefty tariffs, data showed on Thursday.

Outbound shipments came to US$58.2 billion last month, the highest-ever for an April, according to data compiled by the Ministry of Trade, Industry and Energy.

Imports dropped 2.7 percent on-year to $53.3 billion, resulting in a trade surplus of $4.88 billion, reports Yonhap news agency.

Exports to the U.S. decreased 6.8 percent on-year to $10.6 billion, leading to a $900 million drop in Seoul's trade surplus with the U.S. from a year earlier.

The sharp decline in shipments to the U.S. is attributable to a fall in shipments of automobiles, semiconductors and machinery, the ministry said.

Auto exports to the U.S. shrank 16.6 percent to $2.51 billion and chip exports slumped 31 percent to $400 million. Shipments of machinery products decreased 22.6 percent to $970 million.

On the other hand, shipments of petroleum products, rechargeable batteries and wireless communications equipment to the U.S. increased.

"High U.S. tariffs appear to have affected (South Korea's) exports to the U.S., though the degree of impact differs by sector," said Park Jung-sung, Deputy Minister for Trade and Investment at the ministry.

The automotive sector suffered impact partially from tariffs but also from wavering demand for electric vehicles (EVs), he explained.

Exports of auto parts to the U.S., however, increased last month as companies moved to accumulate stocks ahead of planned U.S. tariffs on auto parts starting Saturday (U.S. time), Park added.

Exports to China rose 3.9 percent on-year to $10.9 billion on strong demand for smartphones and semiconductors, and exports to the Association of Southeast Asian Nations (ASEAN) increased 4.5 percent to $9.4 billion thanks to the semiconductor and steel sectors.

Outbound shipments to the European Union surged 18.4 percent to a new monthly record of $6.7 billion, while shipments to India advanced 8.8 percent to $1.7 billion.

By item, semiconductor exports jumped 17.2 percent to reach $11.7 billion, the highest figure for any April, as the price of 8-gigabit DDR4 DRAM went up for the first time in a year, while the demand for high-value products, such as high-bandwidth memory (HBM), also grew.

Exports of wireless communications equipment, including smartphones, expanded 26.5 percent to $1.5 billion, up for the third consecutive month.

Outbound shipments of biohealth products soared 14.6 percent to $1.4 billion, also the highest for any April, and steel shipments added 5.4 percent to $3 billion.

Exports of secondary batteries and ships gained 13.7 percent and 17.3 percent to $700 million and $2 billion, respectively.

But outbound shipments of automobiles, a key export item for South Korea, went down 3.8 percent on-year to $6.5 billion last month on weaker demand for internal combustion engine cars and electric vehicles (EVs).