“The deployment could be completed within one or two months and it can be operational as early as April,” a Seoul military official told reporters according to Yonhap News Agency.

U.S. Forces Korea confirmed the arrival of two THAAD launchers at Osan Air Base south of Seoul a day earlier -- they will be stationed nearly 300 kilometers (186 miles) from the capital in Seongju.

China’s foreign ministry repeated its threat to take necessary steps in response to the move, having reportedly already ordered travel agencies to stop selling packages to South Korea this month among a series of unofficial economic sanctions.

With nearly 30,000 American troops based in the South, THAAD is not the first deployment of U.S. hardware to the peninsula, but Beijing is concerned about the system’s potential spying capability.

Seoul and Washington maintain the battery is aimed at countering North Korea, as the reclusive state continues to develop nuclear weapons -- including with a quadruple ballistic missile test Monday.

In addition to China’s disapproval, South Korea’s main opposition Democratic Party denounced the deployment as rushed and unilateral.

The liberal camp has been calling for the THAAD decision to be deferred until after this year’s presidential election, which could come around May if President Park Geun-hye’s impeachment is confirmed by the Constitutional Court this month.

Acting leader Hwang Kyo-ahn held phone talks with U.S. President Donald Trump earlier in the day, with the pair reaffirming their commitment to hold North Korea accountable for breaching its commitment to United Nations Security Council resolutions.

Anadolu Agency