Assistant Secretary of State for East Asian and Pacific Affairs Danny Russel explained to Reuters on Tuesday that increasing the dosage of sanctions, similar to adjusting a medicine regimen, may be necessary when the desired effects are not achieved. Russel mentioned the potential for new sanctions from the UN Security Council, the United States, or a coalition of countries from the European Union and Southeast Asia, in response to North Korea's recent nuclear tests and missile launches. It is believed that North Korea may conduct another nuclear test soon, possibly before a ruling party congress in early May. A study by South Korea's Korea Institute for National Unification estimated that there could be as many as 150,000 North Korean workers abroad, mainly in China and Russia, who send back up to $900 million annually. North Koreans are known for working overseas in various fields such as restaurants, construction, and as doctors. The success of current or potential new sanctions relies heavily on China, North Korea's neighboring country and largest trading partner, fully enforcing them. US officials and analysts emphasize the importance of China's cooperation in implementing effective sanctions. Chinese Foreign Ministry spokeswoman Hua Chunying urged all parties to avoid escalating tensions and to maintain calm and restraint to facilitate the resumption of talks. When asked about the possibility of supporting tougher sanctions in response to a potential fifth nuclear test by North Korea, Hua Chunying declined to answer, calling it a hypothetical question. In the event of another nuclear test, the United States, South Korea, and Japan may consider taking unspecified defense-related actions, according to officials. He mentioned that as the threat increases, our defensive capabilities should also adapt. He emphasized the possibility of diplomatic negotiations to address North Korea's nuclear program. South Korean Unification Ministry spokesman Jeong Joon-hee expressed skepticism about the effectiveness of engaging with North Korea and suggested focusing more on imposing sanctions. Russel outlined potential responses to a fifth nuclear test by North Korea, noting that sanctions have not been successful in deterring them. He clarified that no decisions have been made regarding a potential fifth test. US General Vincent Brooks, who has been nominated by President Barack Obama to lead American forces in South Korea, stated that China is frustrated with North Korea's behavior, particularly its nuclear advancements. However, China is reluctant to exert pressure that could jeopardize the stability of Kim Jong Un's regime. Brooks also noted that Kim Jong Un appears to be more daring, arrogant, and impulsive than his father, Kim Jong Il, as he continues to ignore international concerns and advance North Korea's nuclear program. Assistant Secretary of State Russel mentioned that it will take time to assess the effectiveness of the latest sanctions, but China has shifted towards applying pressure on North Korea after exhausting other diplomatic measures. Russel also suggested that serious and sustained pressure on North Korea has not been attempted before. The North Korean economy's heavy reliance on China and access to China is so significant that any change in China's approach could potentially mark a new phase. However, Frank Jannuzi, a former Senate Foreign Relations Committee staffer for East Asia and the Pacific, doubts that China has truly shifted its stance and is now willing to exert more pressure on North Korea. Jannuzi believes that while China has economic leverage, they are hesitant to fully utilize it due to concerns about the effectiveness and potential consequences of severe sanctions, such as conflict, refugees, or turmoil.