A South Korean appeals court on Wednesday ordered the government to disclose the results of a probe on pollution detected in the water table near a U.S. Forces Korea (USFK) garrison in Seoul.

The U.S. Army base in Yongsan, central Seoul, has been suspected as the source of oil that has polluted the nearby water table and land.

The Seoul Metropolitan Government has been conducting a water table purification project since 2003 but petroleum-based contaminants above the standard level keep being detected from water near the U.S. base.

The Seoul High Court upheld a lower court's decision which ordered the environment minister to open to the public the result of its joint probe with the USFK.

The two sides agreed in June 2013 to carry out several on-the-spot probes. The first investigation was conducted in May last year, but the authorities did not reveal the outcome to the public.

In August 2015, the Lawyers for a Democratic Society, a group of activist attorneys, filed a petition with a local administrative court seeking disclosure of the information.

The administrative court ruled in favor of the lawyers' association in June, saying there is a low possibility of damaging the national interest even if the result is revealed.

"The Seoul city government has been conducting a water purification process since 2003, but pollutants continue to be detected," the lower court said. "Relevant information should be revealed considering the people's right to know."

"It is hard to say the two countries ties will be damaged even if the information is disclosed, just because the USFK opposes it," the court added.

As people here are aware that the probe has been conducted, if the result is not disclosed it could result in further distrust in the USFK and unnecessary diplomatic issues, it said. (Yonhap)