China has cautioned the United States against taking “discriminatory actions” against its companies, following reports that Washington is planning to ban the sale of vehicles using Chinese and Russian technology. The warning comes amid a simmering trade row between the two nations, which has seen the US impose steep tariff hikes on Chinese imports.

According to Bloomberg and other media sources, the US is mulling new rules that would ban hardware and software made in China from its vehicles. The move is said to be part of an effort to protect national security, although China has rejected the claim, urging the US to respect market principles and provide a fair business environment.

“We oppose the US’s broadening of the concept of national security and the discriminatory actions taken against Chinese companies and products,” said foreign ministry spokesman Lin Jian. “China will resolutely safeguard its legitimate rights and interests.”

The potential ban would be the latest escalation in a trade war that has seen the US impose tariffs on over $300 billion worth of Chinese goods. In May, Washington unveiled tariff hikes on Chinese imports such as electric vehicles and semiconductors, with the rate on EVs set to quadruple to 100 percent this year and the tariff on semiconductors surging from 25 percent to 50 percent by next year.

The move has been met with criticism from China, which has accused the US of “cheating” rather than competing on trade. The trade war has also had implications for global trade, with many countries affected by the tariffs.

The US presidential election is also seen as a factor in the ongoing trade tensions, with both Democrats and Republicans seeking to show a tough stance on China ahead of the polls.