South Korean President Moon Jae-in's approval rating fell this week after he ordered the further deployment of the U.S. Terminal High Altitude Area Defense (THAAD) missile interception system, a weekly survey showed Thursday.

According to the Realmeter poll, President Moon garnered 70.3 percent in support this week, down 3.7 percentage points from the previous week.

It was based on a survey of 1,521 voters conducted from Monday to Wednesday. It had 2.5 percentage points in margin of error with a 95 percent confidence level.

The pollster cited Moon's decision to temporarily deploy four more THAAD launchers as one of the key reasons for his lower approval scores.

The Democratic People's Republic of Korea (DPRK) test-launched what it called an intercontinental ballistic missile (ICBM) around midnight on July 28. The Hwasong-14 flew some 1,000 km and was lofted as high as over 3,700 km.

Right after the DPRK's ICBM test-launch, the South Korean leader ordered his aides to consult with the United States on the additional installation of the remaining THAAD mobile launchers.

On April 26, two mobile launchers and other THAAD elements were transported in the middle of night to a former golf course in Seongju county, North Gyeongsang province. Moon took office on May 10.

Four more launchers were reportedly delivered to a U.S. military base near Seongju. A THAAD battery is composed of six launchers, 48 interceptors, the AN/TPY-2 radar and the fire and control unit.

During the national security council (NSC) meeting, held an hour after the DPRK's missile-firing provocation, Defense Minister Song Young-moo asked President Moon to fully deploy the THAAD battery, according to comments made by Song in the parliamentary defense committee's meeting.

However, the temporary THAAD deployment was decided upon during the NSC meeting, according to the defense chief.

Song said Monday that the "temporary THAAD deployment" had the meaning of reviewing it under the conditions that additional THAAD elements are temporarily installed, while the environmental impact assessment is underway, as the DPRK crossed the red line too fast.

South Korea has said the final decision on whether to deploy the U.S. missile shield would be made after completing the assessment of environmental impact on the THAAD site located in southeast South Korea.

The pollster said the defense minister's remarks caused "policy confusion" about the THAAD installation, citing it as one of the main reasons for the president's lower support rate.

It noted that the temporary deployment decision and the policy confusion expanded the negative sentiment among both anti- and pro-THAAD voters.

Moon's decision to deploy more THAAD elements caused controversy here. Local liberal newspaper Hankyoreh said in a commentary on Monday that THAAD is unable to intercept the DPRK's ICBM, casting doubts on why the Moon government, which had emphasized the procedural legitimacy, hurriedly decided to deploy more THAAD elements.

Local conservative newspaper Chosun Ilbo reported Tuesday that signs of backlash against the further deployment decision were detected from some of the ruling Democratic Party lawmakers.

One two-term lawmaker of the ruling party was quoted by the newspaper as saying he still opposed the installation of the U.S. missile shield in South Korea, pointing out Moon's promise during his election campaign to decide upon the THAAD issue through legitimate procedures, including the parliamentary approval.

Support for the Democratic Party fell 2.1 percentage points over the week to 50.5 percent this week.

Approval scores for the main opposition Liberty Korea Party gained 2.5 percentage points to 17.9 percent, and the centrist People's Party saw its support rise to 6.8 percent.