Seoul, August 11 (Saba) - South Korea said Wednesday it sent North Korea a message urging the prompt release of the crew of a South Korean fishing boat the communist state seized three days ago amid high military tensions, according to Qatar News Agency (QNA).

The message, addressed to the North''s top Red Cross official, contains a call by his South Korean counterpart to free the seven crew members of the Daeseung "promptly in line with international law and customs and on humanitarian grounds," Unification Ministry spokeswoman Lee Jong-joo said.

South Korea is investigating whether the 41-ton boat, which had left for a joint fishing area off the east coast of the Korean Peninsula on August 1, trespassed into the North''s exclusive economic zone.

Pyongyang has yet to offer any word on the state of the crew that included four South Koreans and three Chinese, South Korea''s (Yonhap) news agency reported. "We have also asked the North to explain in detail how the fishing boat was seized," Lee said, adding the Red Cross channel is often used in inter-Korean issues involving civilian boats.

The seizure came amid high tensions between the two Koreas in the wake of the deadly March sinking of a South Korean warship near their western sea border. On Monday, North Korea fired more than 100 rounds of artillery along the Yellow Sea border near the area where South Korea had just ended five-day-long naval drills.

In July of last year, a South Korean fishing boat, the Yeonan, accidentally crossed into North Korea''s waters and was towed to a nearby port. The boat was released about a month later.

Saba