North Korea's fourth nuclear test has drastically raised tensions in East Asia, with regional powers responding to the growing security threat along Cold War lines.

South Korea, the United States and Japan have forged a united front in the face of North Korea's nuclear and missile development and called for strong international sanctions against the Pyongyang regime.

Following the North's long-range rocket launch earlier this week, the three countries pressed the Kim Jong-un regime further by adopting unprecedented sanctions measures at the unilateral level.

In fact, South Korea played what some experts view as its last card by shutting down the inter-Korean industrial complex at North Korea's border city of Kaesong.

At the other end of the spectrum, China and Russia have opposed strong sanctions and advocated the resumption of dialogue as the only way to end the North's nuclear and missile programs.

Tensions between the two sides increased exponentially when Seoul and Washington announced the start of official talks on the deployment of an advanced U.S. missile defense system in the South.

 Beijing and Moscow harbor deep suspicions about Washington's intention to place a Terminal High Altitude Area Defense system on South Korean soil, viewing it as an attempt to put Russian and Chinese military facilities in range of U.S. radar.

Such tensions come against the backdrop of Washington and Beijing's growing rivalry as both sides push to expand their presence in the Asia-Pacific region.

"If the U.S.-China rivalry intensifies, we might end up empty-handed," said Jang Yong-seok, a senior researcher at the unification and peace institute of Seoul National University. "It's important to keep the door to dialogue open even if we disagree with China."

China is reluctant to push the North too hard out of concerns for its own security interests, including the possibility of a major influx of North Korean refugees or a U.S.-allied, unified Korea on its borders.

As Pyongyang's sole major ally and economic benefactor, Beijing has regarded the neighboring country as a key strategic asset in fending off U.S. influence.

"While strengthening our alliance with the U.S., we must focus on finding the lowest common multiple with China," said Kim Yong-hyun, a professor of North Korean studies at Dongguk University in Seoul.

The recent developments have also played out in the form of calls for South Korea's nuclear armament.

"Even among us, there are calls for nuclear armament, but in the long run, that's an option that will bring us more losses than gains," said Lee Sang-hyun, a researcher at the Sejong Institute.

Still, others proposed a cautious review of the possibility of bringing in U.S. tactical nuclear weapons.

"If we were to bring in U.S. tactical nuclear weapons and create a nuclear balance, we would open a whole new level, instead of calling for North Korea's denuclearization while unilaterally being under a security threat," said Kim Hyun-wook, a professor of the Korea National Diplomatic Academy. (Yonhap)