Seoul, Dec 18 : South Korea will work toward coordinating bilateral and trilateral measures involving the US and Japan if North Korea continues to engage in provocations, a senior Seoul security official said on Sunday. Principal Deputy National Security Adviser Kim Tae-hyo made the remarks at Incheon International Airport, west of Seoul, after returning home following his attendance at the second meeting of the South Korea-US Nuclear Consultative Group (NCG) in Washington last Friday. Last week, Kim raised the possibility of North Korea launching an intercontinental ballistic missile (ICBM) in December. North Korea last test-fired a Hwasong-18 solid-fuel ICBM in July, Yonhap news agency reported. "If such provocations from North Korea continue, we will work toward coordinating necessary measures between South Korea and the US, actions the two countries can take individually and joint actions that South Korea, the US and Japan can collectively implement," Kim told reporters after arriving at the airport. Kim added that Washington also "recognises the possibility of North Korea conducting ballistic missile provocations, including ICBMs, by mid-December or at the latest early next year". He noted that the North Korea's potential capability to equip missiles with nuclear warheads was a crucial concern that the NCG needs to be attentive of. Amid renewed North Korean ICBM launch concerns, the USS Missouri (SSN-780), a Virginia-class nuclear-powered US attack submarine, entered a key naval base in Busan, 320 km southeast of Seoul, earlier on Sunday, according to the South Korean Navy. The deployment of the submarine comes just three weeks after the USS Santa Fe (SSN-763), a Los Angeles-class submarine, entered the Jeju Naval Base on the southern resort island. /IANS