South Korea will push for a stronger joint nuclear deterrence strategy with Washington should Pyongyang conduct a third nuclear test, a senior government official said Monday.

The two allies agreed last year to forge a “tailored deterrence strategy” by 2014 to cope with increasing threats from North Korea’s nuclear weapons and other weapons of mass destruction.

“We may have to talk about sure, strong measures when we negotiate with the U.S. (over the deterrence strategy) in the future. We should map out sure responses should our people be put under the threat of the North’s nuclear weapons,” he told reporters, declining to be named.

“After a third nuclear test, the threat would become more real. For that, we should map out a stronger, more concrete one that could have a substantive (impact) on the North.”

His remarks came amid increasing signs of an imminent nuclear test at the communist state’s Punggye-ri site located in the northeast.

The official stressed that what is discussed at the South Korea-U.S. Extended Deterrence Policy Committee is how to cope with the threat from the possible use of nuclear arms while sanctions are what can be adopted in the diplomatic and economic realms with regard to nuclear experiments.

The allies will continue to have working-level talks over the strategy at the EDPC in the first half of this year, he said. They will flesh out their vision over the strategy and have a more concrete form reported at the annual Security Consultative Meeting slated for October.

The EDPC was set up in late 2010 after the allies agreed to step up their commitment to deter the North following its two military attacks on the South that year that killed 50 South Koreans.

As concern has risen that the North’s additional test would bring it closer to securing core technology needed to miniaturize its nuclear warheads, calls have emerged for Seoul and Washington to introduce a stronger nuclear deterrence plan.

President-elect Park Geun-hye called on the North to reverse its plan to conduct the nuclear test, stressing that it should recognize that there would not be anything for it to achieve through provocations.

“It would only face stronger responses from the international community with the test,” she said during a briefing by her transition team’s subpanel on foreign affairs, defense and unification.

“The North should know that the cancelation is the starting point for it to move toward peace and development as a member of the international community.”

Meanwhile, the allies’ top diplomats reaffirmed their resolve to sternly respond to additional provocations by North Korea amid signs of an imminent third nuclear test by the North.

During a 10-minute telephone conversation on Sunday, Foreign Minister Kim Sung-hwan and new Secretary of State John Kerry shared the view that Pyongyang would face “significant action” by the international community in the case of another atomic test.

Their talks came a day before the allies launched three-day maritime drills in the East Sea on Monday in an apparent show of force against the North pushing for a nuclear test at its Punggye-ri site.

The exercise involves top-of-the-line warships from each side including the USS San Francisco, a 6,927-ton Los Angeles-class submarine, and USS Shiloh, a 9,800-ton guided-missile cruiser.

Since the U.N. Security Council adopted Resolution 2087 on Jan. 22, which condemned the North’s December rocket launch, Pyongyang has strongly hinted at conducting a third nuclear test.

On Sunday, the North’s Korean Central News Agency said that its leader Kim Jong-un made an “important decision” to defend national security and sovereignty at an enlarged meeting of the ruling Worker’s Party’s Central Military Commission.

Amid heightened tension on the peninsula, Seoul has stepped up diplomacy to prevent the test, which could put the reclusive state deeper into international isolation.

Lim Sung-nam, Seoul’s special representative for Korean Peninsula peace and security affairs, met his Chinese counterpart Wu Dawei in Beijing to discuss the North’s impending atomic test.

The two officials reportedly shared the view that another nuclear test would pose a serious threat to peace and stability on the Korean Peninsula and undermine denuclearization efforts.

China has repeatedly demanded that the North cancel its test plan. Observers said that Beijing does not want Pyongyang to destabilize the region as it wants to maintain the status quo while focusing on its internal issues such as income disparities and political reforms.

Apart from diplomacy, Seoul is also in close consultation with concerned parties such as Washington and Tokyo over how to sanction the North should it carry out the test. Seoul officials warned that sanctions tougher than those entailed in UNSC Resolution 2087 would be applied.

Meanwhile, Seoul’s Unification Ministry said it would toughen its inspection of items that are transported from the South to the North including the inter-Korean industrial complex in Gaeseong of the North.

In its policy report to the National Assembly’s foreign affairs and unification committee, the ministry explained that the stepped-up inspection was to more tightly scrutinize the items from the South so that those banned under U.N. resolutions would not enter the North.

“We will more effectively carry out the U.N. resolutions sanctioning the North and make the North pay for the price that corresponds to the level of its provocation,” the ministry said in the written report.

Regarding a question whether Seoul would restrict the number of South Koreans working in the Gaeseong complex after a possible nuclear test, Unification Ministry spokesperson Kim Hyung-suk refused to comment, wanting to maintain “constructive ambiguity.”

In its report, the ministry also said that Pyongyang would try to gain nuclear-power status based on its successful rocket launch in December, and that it would seek to negotiate with the U.S. over nuclear arms reduction and security assurances.

By Song Sang-ho (sshluck@heraldcorp.com)