South Korea says it will restrict financial dealings with more than 100 additional groups and individuals with suspected links to Iran's nuclear program.
Friday's announcement by the Finance Ministry is part of a U.S.-led campaign to enforce sanctions against Iran after a United Nations report said Tehran was advancing its nuclear arms program.
Iran says its nuclear program is for peaceful purposes.
The South Korean ministry says 99 organizations and six individuals will be added to its sanctions lists. South Korea already has similar sanctions in place against more than 120 entities.
The ministry didn't say which groups would be sanctioned. It also didn't include measures against crude oil imports from Iran.