The South Korean government has canceled or postponed officials' visits to the border region between North Korea and China out of terrorism concerns, a public institute under the unification ministry said Thursday.

The Institute for Unification Education said that it has indefinitely postponed its education program for government officials and those from publicly owned enterprises, which was initially slated to start at the end of this month.

About 60 senior and mid-level officials from several government ministries and public enterprises were to visit areas near North Korea and China as part of the institute's tour program for national unification policy.

According to an official at the institute, 30 other trips to the border area for the education of public officials have been scrapped, with the trips being diverted to other regions.

The National Unification Advisory Council, meanwhile, sent official documents to organizations under its wing asking them to refrain from making trips to the Sino-North Korean border.

The council noted the foreign ministry's recent travel warning advisory amid North Korea's provocative actions, as well as tense Northeast Asian relations.

On May 16, Seoul called for cooperation from local tour agencies to discourage its nationals from visiting areas bordering North Korea.

The Foreign Ministry hosted a rare group meeting with representatives of around 10 major firms specializing in arranging overseas tours. It was meant to enhance awareness on the need to take stronger safety measures for South Koreans abroad and solicit cooperation.

Concerns have grown about the possibility of North Korea kidnapping South Koreans or carrying out other unpredictable terror attacks.

An ethnic Korean pastor, who assisted North Korean defectors, was recently murdered in the Chinese northeastern province of Jilin. North Korean agents are allegedly behind the killing.

Pyongyang also openly threatened to "retaliate" unless Seoul repatriates 13 North Korean restaurant workers who defected here last month.

Many South Koreans visit the North Korea-China border area, where Mount Paektu and relics of the Koguryo kingdom (37 B.C.-668 A.D.) are located. (Yonhap)