A Seoul court has sentenced a pro-North Korea activist to four years in prison for breaking South Korean law by visiting Pyongyang illegally and praising the country.

The Seoul Central District Court says it sentenced No Su-hui on Friday for traveling to North Korea from China last year to honor Kim Jong Il 100 days after the North Korean leader's death.

Visiting North Korea without government approval is punishable by up to 10 years in prison under South Korea's National Security Law.

Tension is high on the Korean Peninsula as Pyongyang appears to be preparing for its third nuclear test. No's organization didn't answer a call looking for comment Friday.

The two Koreas are still technically at war after the 1950-53 Korean War ended in a truce.