SEOUL - In the wake of North Korea's third nuclear test, the security dynamics in the region appears to be entering a new phase as Seoul and Washington push for more potent sanctions and craft ways to beef up their deterrence capabilities.
President Lee Myung-bak and his US counterpart Barack Obama pledged to work out a stronger response and maintain Washington's nuclear umbrella to protect South Korea during a phone conversation late Tuesday.
They agreed to "seek a range of measures aimed at impeding North Korea's nuclear and ballistic missile programmes and reducing the risk of proliferation," the White House said in a statement.
"President Obama unequivocally reaffirmed that the United States remains steadfast in its defence commitments to the Republic of Korea, including the extended deterrence offered by the US nuclear umbrella."
Lee also spoke over the phone with Japanese Prime Minister Shinzo Abe.
Next week, military officials from the two countries will meet in Washington to discuss their nuclear deterrence strategy, defence sources said Wednesday.
The two allies aim to establish a tailored nuclear deterrence plan by the end of 2013. They are likely to expedite the consultations in line with the North's elevated nuclear threat.
The UN Security Council strongly condemned the detonation during an emergency closed-door meeting Tuesday and vowed action against the "grave violation" of its resolutions.
South Korea and the US are pushing for a fresh round of powerful sanctions despite China's lukewarm participation. They are calling for measures in line with "significant action" codified in the council's recent resolution designed to punish Pyongyang for its December 12 rocket launch. Seoul currently holds the presidency of the council this month.
The multilateral mechanism aside, Seoul and Washington are also considering separate, country-level sanctions that are more enforceable and can inflict a bigger blow on its nuclear programmes, such as possibly targeting the North's financial assets or sea transport.