As trade talks between the U.S. and China increasingly center on Chinese treatment of foreign companies, Beijing says major American complaints about structural aspects of its economy are running up against "core interests."

The implication: Those matters are not up for negotiation.

Previously, the vague "core interest" term was generally understood as referring to Beijing's territorial claims, such as those on Taiwan. But a commentary piece published this weekend by state news agency Xinhua emphasized that China will not yield on its prerogative about how to manage its economy.

The Chinese-language article published Saturday claimed there were five ways in which the U.S. is harming the growth of the global economy by launching a trade war with the Asian giant.

"At the negotiating table, the U.S. government has made many arrogant requests, including restricting the development of state-owned enterprises," the commentary said, according to a CNBC translation. "Obviously, this is beyond the field and scope of trade negotiations, (and) touches upon China's fundamental economic system."

"This demonstrates, that behind the trade war the U.S. has launched against China, there is an attempt to violate China's economic sovereignty, (and) compel China to damage its own core interests,“ the article said.

China's giant state-owned enterprises control strategic industries such as energy, telecommunications and defense. Since those companies benefit from favorable policies and subsidies, foreign companies complain of an unfair advantage. The escalating trade dispute between the U.S. and China has focused the coerced surrender of proprietary technology and the trampling of intellectual property rights.

Critics say China has been able to benefit economically from joining the World Trade Organization in 2001 without following through on commitments to reduce state control. For its part, Beijing has made some effort to increase the role of the market in its economy and allow foreign companies greater access — but many outside observers say it's too little, too slowly.