North Korea said Wednesday an intercontinental ballistic missile it had test-fired a day earlier had achieved successful re-entry into the atmosphere.

Atmospheric re-entry is a difficult technology in developing ICBMs. The North also said its missile could carry a large nuclear warhead.

Although its announcements are not credible, South Korea and the US have acknowledged the missile as an ICBM.

In light of the development, their responses should be entirely different from the past. Therefore, the South Korea government responded more firmly than ever to the North’s missile provocation.

Its military and the US forces in Korea fired off ballistic missiles into the East Sea in a simulated precision strike against enemy headquarters in Pyongyang, and disclosed footage of the joint missile drill. It was the first time for the South to show its missile force in response to the North’s missile or nuclear provocations.

The joint exercise came less than a day after Pyongyang’s claim of a successful test of an ICBM, which can reach the western coast of America.

President Moon Jae-in said, “North Korea’s serious provocation required us to react with more than just a statement.”

Talks of peace not buttressed by force are hollow, so the show of force was appropriate.

It is noteworthy that Moon suggested the joint missile drill to US President Donald Trump, who agreed to it. Taking initiative in responding to the North’s provocations deserves recognition. The joint missile exercise was also meaningful in that it showed the solid US-Korea alliance, which Pyongyang has sought to crack.

Furthermore, sanctions sought by Washington are expected to be tougher than ever.

“We will never accept a nuclear-armed North Korea,” Secretary of State Rex Tillerson said in a statement, “We intend to enact stronger measures to hold North Korea accountable.”

“Any country that hosts North Korean guest workers, provides any economic or military benefits, or fails to fully implement UN Security Council resolutions is aiding and abetting a dangerous regime.”

US Ambassador to the UN Nikki Haley said during a UN Security Council meeting that the US will use military force against North Korea if necessary.

US military augmentation around the Korean Peninsula and the expansion of a secondary boycott to block the North’s trade with any countries are likely.

North Korean leader Kim Jong-un said after watching the ICBM test, “We will never put our nuclear weapons and ballistic missiles on the negotiation table, unless the US’ hostile policy and nuclear threat to us is removed.”

This may sound familiar. He has repeated that atomic weapons and missiles are not negotiable. However, his remark also indicates that he will negotiate only with Washington, if negotiations take place. The South should be wary of Pyongyang’s strategy to leave Seoul out of a meeting with Washington over its nuclear and missile programs.

One worrisome scenario now is the possibility of the North’s sixth atomic bomb test. Chances of it taking place look higher than ever, now that the North has tested an ICBM and needs miniaturized nuclear warheads.

If it conducts a nuclear test, the communist state will clearly cross the “red line.” With the ICBM launch, a warning light came on.

It is time for the South Korean government to talk China into turning up the pressure on Pyongyang.

As the North has snubbed the South’s dialogue offers without any hesitation, a change in the tone of the South’s North Korea policy has become inevitable.

Peace gestures are not bad, but now is not the time for them.

The best solution in the current situation is to pressure Pyongyang to stop provocations and come to the negotiation table. The pressure should be strong enough to threaten the Kim regime.

Moon left for Germany on Wednesday to attend the G-20 summit. He should utilize his meetings with leaders of the US, China and Japan to ramp up responses to the North’s ICBM provocation.

It would be difficult to persuade China, which has repeated calls for restraint and dialogue, but strong measures the country could take, including the suspension of oil supply to the North, are needed now more than ever.