The United States and South Korea are expected to hold the first meeting of a joint working group aimed at discussing the proposed deployment of the THAAD missile defense system "within a week," the commander of U.S. Forces Korea said Wednesday.

Gen. Curtis Scaparrotti told the House Armed Services Committee that it will take some time to deploy the Terminal High Altitude Area Defense system to the South as the working group has to determine the right location and other details.

"We're forming a joint working group that I think will have its first meeting within a week," he said. "THAAD is a complex system.

It's going to take some time for us to find the right location because where you locate it makes a difference on how effective it is. So we've got to find the right location and do that work, which we will do in accordance with our SOFA."

SOFA refers to the Status of Forces Agreement that governs the U.S. troop presence in South Korea.

Scaparrotti also reiterated the importance of the THAAD deployment.

"You are well aware of the large arsenal that North Korea has in ballistic missiles that is growing in strength, but also in accuracy," the commander said. "I think that the discussion we're having right now to add THAAD to Korea is very important. We need THAAD there to have a layered defense."

Shortly after the North's Feb. 7 missile test, South Korea and the U.S. jointly announced they would begin official discussions on the possible placement of the THAAD system in South Korea.

China strongly protested the decision, despite repeated assurances from Washington that the system is aimed only at countering North Korean threats.

On Tuesday, U.S. Secretary of State John Kerry emphasized that the only reason for the U.S. and South Korea to consider THAAD deployment is because of North Korean threats, and the system wouldn't be necessary if the communist nation were denuclearized.

U.S. Pacific Commander Adm. Harry B. Harris Jr. criticized China's opposition to THAAD, saying it is "preposterous that China would try to wedge itself between South Korea and the United States for a missile system designed to defend Americans and Koreans."

A defense official in Seoul confirmed the timing of the joint working group's launch for next week.

"Signing terms of reference for the joint working group this week will be physically impossible," the official said, asking not to be named. "It will carry into next week."

Initially, South Korea's Defense Ministry and USFK had planned to sign the terms on the launch of the joint group on Tuesday.

But shortly before the scheduled signing, the allies announced a delay, saying it will take one or two more days to iron out details.

The delay is attributable to unfinished discussions between USFK and the U.S. government, deputy defense ministry spokesman Nah Seung-yong said in a regular briefing.

"USFK should finalize internal discussion with the U.S. government, based on which it will sign the terms of reference with U.S.," Nah noted. (Yonhap)