On Thursday, the Ministry of Commerce (MOC) announced adding Lockheed Martin Corp and Raytheon Missiles & Defense to its "unreliable entity list", prohibiting the two US weaponry companies from engaging in imports and exports related to China, or making new investments in the country.

For those familiar with the US waving the sanction club called "entity list", China's using the same measure should not come as a surprise. The MOC has stated clearly in its statement that the move is in accordance with laws on national security and trade, totally legal and normal. Sanctioning has always been an option and China is cautious to use it for punishing those violating its core interests.

The Taiwan question is one of China's core interests and brooks no external interference. By selling missiles and fighter planes to Taiwan, the two companies have undermined China's core interests by supporting pro-independence forces on the island, making the sanction justified.

China will always keeps its door open to any legal foreign business but will not hesitate to punish those profiteering from sabotaging its sovereignty and territorial integrity.