China lodged a complaint on Monday to the World Trade Organization regarding the United States' proposed tariffs on $200 billion worth of Chinese imports, the Ministry of Commerce said in a statement.

It followed the recent complaint that the ministry filed on July 6 to the WTO about the US' early round of levies on $34 billion worth of Chinese goods.

US tariff hikes targeting Chinese goods were based on Section 301 of the Trade Act of 1974, its domestic trade law.

"The US' unilateral initiation of a trade war has no international legal basis at all," the ministry said last week in a point-by-point response to the US statement under Section 301.

The US unilaterally launched a Section 301 investigation against China last year despite opposition from China and the international community.

It released an investigation report in March, and imposed tariffs on $34 billion worth of Chinese goods on July 6 in disregard of 91 percent opposition in the comments it received.

"The (US) tariffs are typical unilateralism, protectionism and trade bullying. They are a clear violation of the basic WTO principle of most-favored-nation treatment as well as the basic spirit and principles of international law," the ministry stressed.

Wan Zhe, chief economist of International Cooperation Center with National Development and Reform Commission, said the real intention of the US government initiating trade conflicts with other countries is to distract attention from its internal contradictions, such as the wealth gap and job losses.

Against such a backdrop, what China should do is to continue to push ahead with economic reform and opening-up, and work with the rest of the world to support free trade and multilateralism, Wan said at a recent seminar.

Dong Yan, a senior researcher at the Chinese Academy of Social Sciences, said China should firmly uphold the multilateral trading system while sticking to its established agenda of further opening-up.