The United States and others must continue to enforce sanctions on North Korea to prevent the North from proliferating its nuclear capability, the nominee for US under secretary of defense for policy said Thursday.

Colin Kahl also highlighted the need for South Korea and the United States to maintain their combined defense posture to deter North Korean threats.

"I believe that it is the role of the Department of Defense to maintain a robust defense and deterrence posture, and to ensure that the United States is well-positioned with forces and assets throughout the region to detect and respond to DPRK threats," Kahl said in a written answer submitted to the Senate Armed Services Committee prior to his confirmation hearing.

DPRK stands for North Korea's official name, the Democratic People's Republic of Korea.

"We must also continue to pursue robust sanctions enforcement to mitigate the nuclear proliferation threat posed by North Korea," he added.

The US is currently undergoing a comprehensive review of its policy toward North Korea that it said will lead to a new approach to how to deal with the nuclear-armed state.

North Korea has conducted six nuclear tests so far, with the last one being held in September 2017.

"This strong defense posture must underpin our efforts, irrespective of the outcome of the strategy review, to ensure that the United States engages the DPRK from a position of strength," said the former national security adviser to then-Vice President Joe Biden in 2014-2017.

Kahl noted the Korean Peninsula is "inextricably" tied to regional security and stability, and said the US is currently "well-postured" to deal with security threats posed by North Korea.

The US is also undergoing a global defense posture review that will determine where the US requires more military presence or less.

The US currently maintains some 28,500 troops on the Korean Peninsula.

Kahl said US forces in South Korea and Japan provide a powerful deterrent to North Korean threats.

"If confirmed, I will look to ensure that US forces have what they need to maintain our robust deterrent and readiness posture in Northeast Asia, in close collaboration with our regional allies," he said.

He also underscored the need for flexibility with US forces to ensure readiness.

"The United States must maintain operational flexibility to ensure that our forces are optimized and ready to meet emerging threats to US forces and allies and partners in the region and around the world," he said.

Still, the nominee said, "Our force posture in South Korea ensures our ability to 'fight tonight' alongside our ROK allies, and it is critical to regional stability," referring to South Korea by its official name, the Republic of Korea.

He added, "The US- Republic of Korea (ROK) alliance is critical not only to the security of the ROK, but also to the stability of the Indo-Pacific region — the Department's priority theater." (Yonhap)