The US' unsolicited allegations or sanctions against other countries are against UN norms, even though many of the victim countries and enterprises are reluctant to challenge them. In Iran's case, the US has unilaterally extended the previous UN sanctions citing violation of nonproliferation norms. This has hurt Iran's economy and society, and even the normal business connections between Iran and other countries.

Such sanctions are unlikely to endanger US businesses in Iran, though, because of the tense Washington-Teheran relationship and the limited commercial intercourse between them. But the sanctions pose a threat to many companies in China, Japan and Europe that are deeply engaged in trade with Iran.

The US has used its dwindling dominance in the global financial field to unilaterally impose sanctions on other countries. Actually, the US has been practising unilateralism in diplomacy since the end of the Cold War when the collapse of the Soviet Union made it the sole superpower. Since its global military dominance is on the decline, the US has started exploiting the intensified globalization process by imposing economic sanctions on other countries, even some major ones, to force them to comply with its policies.

Besides, Washington uses sanctions also to deal deadly blows to its competitors in the financial world for example, it has made frequent efforts to suppress the rise of the euro by imposing huge fines on prime European banks for "doing business" with Iran.

With its increasing economic growth, China has often been the target of the US' unilateral sanctions, sometimes for economic reasons and at others for its connections with the "troubled countries". More Chinese enterprises and individuals are likely to suffer because the US is expected to keep imposing direct and indirect sanctions on China. The recent US sanction on Russia over the Crimea crisis shows that Washington is ready to put pressure even on major powers, which is something China should pay special attention to.

China has always advocated cooperation and dialogue as opposed to taking compulsory or unilateral measures to resolve international disputes. Sanctions, China insists, can be legitimate only if they are authorized by the UN. One country should not impose sanctions on another just because its domestic law has been violated. China should be ready to hold negotiation with the US to protect its legitimate interests and to ensure its economic security. At the same time, it should garner the international community's support to urge the US government to change its global outlook and adhere to a fair and justified global financial order in which unilateralism has no place.

The author is deputy director of the Institute of American Studies, China Institutes of Contemporary International Relations.