A group of representatives from South Korea's presidential panel returned home Sunday after a trip to North Korea, where they discussed possible trilateral economic cooperation involving the two Koreas and Russia, its official said.

The Presidential Committee on Northern Economic Cooperation sent an 11-member team led by committee chairman Song Young-gil to the North's northeastern border region of Rason. They stayed there for two days from Friday.

The team originally planned to attend a seminar hosted by Russia to discuss trilateral economic cooperation involving the two Koreas and Russia but canceled its participation. Instead it had discussions with North Koreans and Russians on the Rajin-Khasan project and other issues, the official said.

Rason, formerly known as Rajin and Sonbong, was designated as a special economic zone in 1991. The North has sought to develop the zone by drawing outside investment but faced setbacks amid its continued provocations.

The Rajin-Khasan project, in particular, is a logistics project aimed at transporting coal from Russia to the North by using a 54 km-long railway linking Khasan in Russia to the Rajin port of North Korea and then to South Korea by ship.

There have been test operations of the transport route three times, including the latest one in November 2015.

The trilateral cooperation project, however, has been put on hold as South Korea banned maritime transport from the North in early 2016 in the wake of the North's nuclear and missile provocations.

South Korea and the United States have said that full-fledged economic cooperation with the North should wait until it carries out its promised "complete denuclearization."

"The Rajin-Khasan project is not subject to UN sanctions but to sanctions imposed by the US So we plan to draw up and propose a broad picture and make preparations for joint study until there is progress in denuclearization and discussion begins on lifting those sanctions," the panel official said. (Yonhap)