Trade volume between South and North Korea reached $958 million in the first seven months of the year, down 16 percent from a year earlier, Seoul's customs office said Monday.

According to data provided by the Korea Customs Service (KCS), the South's exports to the North came to $447 million in the January-July period, down 14 percent a year earlier, and imports dropped 18 percent on-year to $511 million.

The figures suggest that a joint industrial complex in the North's border city of Kaesong, a key source of inter-Korean trade, has been affected by South Korea's sanctions imposed on the North for its two deadly attacks on the South last year.

The industrial complex, an achievement of the first-ever inter-Korean summit in Pyongyang in 2000, combines South Korea's capital and technology with the North's cheap labor.

More than 47,000 North Koreans work at about 120 South Korean firms operating in the industrial zone to produce clothes, utensils, watches and other goods.

The two Koreas remain technically at war as their 1950-53 conflict ended in a truce, not a peace treaty. (Yonhap News)