China has for the first time invoked a law targeting companies that comply with foreign sanctions Beijing rejects, escalating its pushback against U.S. blacklisting of several oil refineries over purchases of Iranian crude, Reuters reported.

China’s Ministry of Commerce on Saturday ordered companies not to comply with U.S. sanctions against five refiners, including the recently designated Hengli Petrochemical, according to Reuters. The order cites a law that allows Beijing to retaliate against entities enforcing sanctions it deems unlawful.

In recent weeks, Washington and other Western governments have sanctioned a number of Chinese firms for trading Iranian or Russian oil, drawing repeated criticism from Beijing. Hengli Petrochemical has denied U.S. allegations that it traded with Iran, the news agency said, noting that independent refiners in China are the main buyers of Iran’s oil exports.

“Any company considering skirting U.S. sanctions should think twice,” a White House official told Reuters, without elaborating on the Chinese order.

Under the law, which was introduced in 2021 and most recently revised in April, China can impose countermeasures on companies and individuals, including trade and investment curbs and entry and exit restrictions, according to Reuters. Legal analysts told the news outlet the law leaves counterparties of sanctioned firms caught between jurisdictions, risking violations of Chinese law if they comply with foreign sanctions or penalties elsewhere if they do not.

Canada’s Trade Commissioner Service warned companies operating in China last August that they could be squeezed between U.S., European Union, and Chinese rules because of the legislation, the report said.