GM Korea, the South Korean unit of General Motors, said Monday its June sales fell 21 percent from a year earlier due to weak domestic demand.

GM Korea sold a total of 43,692 vehicles in June, down from 55,077 units tallied a year earlier, the company said in a statement. 

Exports declined 13 percent to 32,237 from 37,019 over the cited period. Domestic sales also plunged 37 percent to 11,455 units from 18,058 during the same period, it said.

The sales slump was mainly affected by the sharp decline in local demand for the midsize Malibu, flagship Impala and the large-size Alpheon sedan last month, the statement said.

In the second half, the company said it will boost sales through "aggressive marketing."

In the January-June period, GM Korea saw its combined sales decline 9.3 percent on-year to 278,998 units from 307,512, it said. (Yonhap)