President Moon Jae-in said in an interview with Reuters on Thursday the entire process of deploying the Terminal High Altitude Area Defense anti-missile system was accelerated “for some reasons that I do not know.”

In July last year, Korea and the US agreed to deploy the missile shield in Korea.

He said in the interview the original agreement was to deploy one launcher by the end of this year and the remaining five launchers next year.

He reportedly had not known the acceleration of the schedule until he was briefed after taking the presidential office.

US forces in Korea have brought in six launchers. In late April, two launchers and radar entered the site of the system in Seongju, North Gyeongsang Province. The remaining four launchers are on standby in a US base outside the site.

Then, he said Korea and the US originally agreed to deploy just one launcher this year.

His words contradicting the actual deployment came out of the blue and are not readily understood.

“One launcher this year and five launchers next year, or two launchers this year and four launchers next year, those things do not matter essentially. Problem is the process was accelerated,” the presidential office said.

A plan or policy can change depending on the situation.

US Defense Secretary James Mattis and his Korean counterpart Han Min-koo announced in February after their talks in Seoul that the THAAD battery would be deployed and operated within this year.

There was speculation that the previous administration may have tried to deploy the system as fast as possible before the presidential election.

But at that time North Korea had escalated missile provocations. This might have been a compelling reason if Seoul and Washington decided to accelerate the deployment process.

The South Korean Ministry of National Defense keeps silent about Moon’s remark on the accelerated process. However, the US military said that the whole deployment process of the system had been “transparent.” In some ways, this comment may be seen as a challenge to his words.

Moon may easily get an answer to why the process was accelerated, merely by asking related officials. Yet he said, “For some reasons I do not know.”

The president has the authority to review government policy processes if he needs to, even though they were taken by past administrations.

Words such as “I did not know the arrival of launchers,” “I was not briefed,” and “I do not know why” do not seem to be for president to say.

It is justifiable to raise issues about the system, but rekindling controversy is not the right thing to do at this point in time.

The Korea-US summit will be held this week to deal with the grave matter of security on the Korean Peninsula.

North Korea is on the verge of making a nuclear bomb. Last week it tested a rocket engine for an intercontinental ballistic missile, which can strike the US.

Recently, one of its drones infiltrated deep into the South Korean airspace, taking aerial photos of the THAAD site. Suspicious movements were detected at a nuclear test site in North Korea.

THAAD is an important defense weapon to protect South Korea from the North missiles.

Differences settled in the process of THAAD consultations should be dealt with prudently within the government. It is doubtful if disclosure of details to the press was appropriate.

Thousands of people protested against the THAAD deployment on Saturday near the US Embassy in Seoul.

What’s worrisome is controversies Moon has raised about the THAAD may incite such protests.

The Asahi Shimbun newspaper in Japan reported on Saturday that the US had reiterated its call for South Korea to complete the THAAD deployment by the end of the year, and Cheong Wa Dae denied the report.

Controversy is prone to cause unsolicited speculations and unnecessary misunderstanding.

Moon needs to think carefully who will benefit from THAAD controversies.

Remarks which can invite misunderstanding ahead of the summit will do more harm than good.