The cars were worth $15.58 billion, also down 9.8 percent.

In contrast, US vehicle imports here surged 22.4 percent last year to a record 60,099, the data showed.

US President Donald Trump has threatened to impose hefty tariffs on imported vehicles, as a way of prodding global automakers to build plants in the US and create more jobs there.

Last year's sluggish auto shipments to the US was because Hyundai Motor Co. and its smaller affiliate Kia Motors Corp. -- the country's top two automakers -- suffered a series of labor strikes, which cut their output amid increased competition.

Hyundai Motor exported 335,762 units to the US last year, down from 368,172 the previous year, while Kia Motors also saw its shipments to the US drop 27 percent to 332,470 units last year.

Since the global financial crisis in 2009, South Korea's auto shipments to the US had been on a steady rise, partly aided by a free trade deal with the US.

However, there are concerns that free trade could suffer a setback under the Trump administration.

Trump, who blamed free trade for many American economic woes, has denounced the free trade agreement with South Korea as a disaster, though he stopped short of directly saying he would seek to renegotiate it.

Attempts to revise or renegotiate the agreement could set off diplomatic tensions between Seoul and Washington. (Yonhap)