South Korea has asked North Korea to grant immunity to South Korean officials to be stationed in a liaison office the two Koreas recently agreed to establish in the North's border city of Kaesong, sources said Tuesday.

The two Koreas agreed last week to open a liaison office in the city "at an early date" at high-level talks to discuss steps for implementing promises made by their leaders in the historic April and May summits.

South Korea plans to station its officials there in order to keep communication channels open around the clock as part of efforts to support cross-border exchanges, which are likely to increase.

According to the sources close to the matter, South Korea's government recently proposed the North grant immunity from arrest and detention for its officials to be stationed in the office, just as the Vienna Convention grants such privilege to diplomats.

In addition, it also proposed that the North guarantee safety of passage and communications for its officials, while exempting them from checks on their bags and pouches, the sources said.

Kaesong is the western border city in the North where the two Koreas operated a joint industrial complex since 2004. It was hailed as a successful example of economic cooperation between the two Koreas as it married South Korea's capital with the North's cheap and skillful labor.

South Korea, however, closed its operations there in early 2016 and brought its officials and workers back in protest at the North's continued missile and nuclear provocations.

Though there was an agreement regarding the safety of South Korean personnel at the time, there was no clear legal ground for the South Korean government to ask for the return of its people in case of their arrest or detention, experts said.

It is not clear how the North has reacted to the recent proposals.

The unification ministry, which handles inter-Korean relations, said that it has made proposals to the North over the operational details of the liaison office but declined to confirm whether the demand for immunity was made.

"It is true that operation-related proposals were made but we have not yet started consultations with the North on the matters," a ministry official told reporters on condition of anonymity. "It will not take much time to see the opening of the office, so things will be clarified soon."

Earlier, it was reported that South Korea will send an advance team to Kaesong before June 15 to make preparations for the agreed-upon launch of the office. The ministry official said that the composition and scale of the advance team and other details have not been finalized.(Yonhap)