With the U.N. Security Council approving tougher sanctions on North Korea, all eyes are on China, the North's economic lifeline. Still, it remains to be seen whether Beijing will vigorously implement the new sanctions. 

Questions about the sanctions regime have persisted as North Korea has continued to develop its nuclear and ballistic missile programs despite a raft of U.N. sanctions, mainly because of China's lack of vigorous cooperation. 

The Security Council has endorsed four sanctions since North Korea's first nuclear test in 2006, banning the North from trading weapons of mass destruction, importing luxury goods and trading in arms. 

China accounts for nearly 90 percent of North Korea's foreign trade and supplies almost all of the North's energy needs.

China's official customs data show that Beijing has not exported crude oil to Pyongyang since early 2014, but many analysts believe that Beijing is supplying the energy resource in the form of aid, which is not subject to be tallied.

Persuading China to put enough economic pressure on North Korea to abandon its nuclear ambition is tricky because Beijing's leadership views Pyongyang as a buffer between China and U.S. troops stationed in South Korea. 

China's top priority on the Korean Peninsula also appears to maintain stability in North Korea, instead of denuclearizing the wayward ally. 

New U.N. sanctions are likely to make the lives of the North Korean elite uncomfortable, but China is unlikely to put crippling sanctions on the North because a sudden collapse of the regime could spark a refugee crisis at its border and lead to a pro-U.S., democratic Korea on its doorstep, analysts claimed.

Steve Chung, a senior researcher at Hong Kong International Relations Research Association, a civilian think tank, said bilateral trade between North Korea and China may be affected by the new U.N. sanctions for the time being. 

Chung, however, said China is likely to continue its investment in North Korea to strengthen its influence over the North because infrastructure investment in North Korea is not on the list of sanctions. 

The new U.N. sanctions call for U.N. member states to limit imports of North Korean mineral resources, including coal and iron ore, but trade of such minerals could be allowed if it is for "livelihood purposes." 

A diplomatic source in Beijing said it would be very difficult to determine what "livelihood purposes" are in bilateral trade between North Korea and China. 

"Although the draft resolution is a strong one, it remains to be seen whether it can really bite," the source said on the condition of anonymity. 

China's foreign ministry has said Beijing "will earnestly implement" the new U.N. sanctions on North Korea, but "sanctions should not affect the normal lives of North Korean people." (Yonhap)