China on Thursday expressed concerns over the "glass door" or "swing door" restrictions on Chinese investment by the United States citing national security concerns.

"Glass door" or "swing door" indicates barriers that are deliberately set by governments to stop foreign direct investment in certain businesses, driven largely by political and economic purposes, but having nothing to do with national security issues.

"We do not oppose normal security reviews by relevant countries over foreign investment," said Gao Feng, a spokesman for the Ministry of Commerce.

"We hope relevant countries can take effective measures to create fairness for investors from all countries, including Chinese companies for a fair, open, predictable investment environment."

His comments came after China's Huawei Technologies Co Ltd suffered a major setback on Tuesday when its US partner AT&T Inc reportedly dropped a deal to sell the company's smartphones at the last minute under political pressure from US lawmakers.

The Committee on Foreign Investment in the United States, or CFIUS, also blocked China's Ant Financial, a private company, in its $1.2 billion acquisition deal of US money transfer company MoneyGram International Inc last week, citing national security concerns.

"As far as the Ant Financial case is concerned, we regret to see that a normal business investment and a merger made by a Chinese company in the US was once again blocked because of the so-called national security reasons," said Gao.

Trade between China and the US reached $527.22 billion in value between January and November in 2017, up 12.8 percent year-on-year. China, in the meantime, gained a trade surplus of $251.26 billion, growing 9.7 percent from the same period a year earlier, according to data from the General Administration of Customs.

To protect its own interests, the US government launched a Section 301 investigation into Chinese intellectual property and technology transfer, self-initiated probes into Chinese-made aluminum products in December, and rejected China's market economy status at the World Trade Organization.

Gao said China is against trade protectionism in any form. The country will take all necessary measures to ensure the legitimate rights of Chinese companies if the US insists on adopting unilateral acts regarding trade protectionism.

"The trade imbalance is caused by the distribution of the global value chain and the differentiated industrial structure," said Xue Rongjiu, deputy director of the Beijing-based China Society for WTO Studies.