The government has rejected calls to disclose information on the possible deployment of an advanced missile defense system to South Korea, a civic group said Thursday.

The Ministry of National Defense dismissed the information disclosure request filed by the Lawyers for a Democratic Society last month, the group said.

It had asked the ministry to open the terms of reference it signed with its U.S. counterpart and clarify whether the agreement was a treaty, according to the association.

In the aftermath of North Korea's fourth nuclear test in January and launch of a long-range rocket in February, South Korea has launched formal talks with the United States to deploy a Terminal High Altitude Area Defense (THAAD) missile system in the country.

The ministry said the terms of reference is a classified document that is subject to receive secret protection until Dec. 31, 2026, according to the group.

The defense ministry said that Articles 2 and 4 of the mutual defense treaty between the allies and Articles 2 and 5 of the SOFA are applicable to the talks. SOFA refers to the Status of Forces Agreement that governs the U.S. troop presence in South Korea.

The lawyers' association said the clauses indicate that South Korea will provide a post to deploy THAAD in the country and bear the expenses to expropriate the land. (Yonhap)