Any decision by the U.S. to impose new sanctions on China or individual Chinese firms doing business with Russia is the biggest concern for stock investors, according to veteran investor Mark Mobius.

“We must remember how much money has already been lost by investors who had substantial amounts of stocks in Russia and then those who lost money on the Chinese stocks impacted by the Chinese government crackdown,” Mobius wrote in an emailed response to questions.

His comments come as China’s close ties with Russia are emerging as another risk for investors in the Asian nation’s stocks, which have already been battered by Beijing’s regulatory crackdown. Panic selling gripped the market on Monday, with a gauge of Hong Kong-listed Chinese shares tumbling the most since 2008. The rout followed a report that cited U.S. officials as saying that Russia has asked China for military assistance for its war in Ukraine.

Chinese Foreign Ministry spokesman Zhao Lijian rejected the reports of the Russian request as “disinformation” and “malicious.”

Tech stocks were once again at the forefront of the losses in Hong Kong on Monday, with the Hang Seng Tech Index sinking a record 11%. That’s after the Golden Dragon Index, which tracks American depository receipts of Chinese firms, plunged 10% for two consecutive days last week -- a first in its 22-year history.

The selloff in ADRs “can get worse if there are implications for China as regards to Russian sanctions,” wrote Mobius, who set up Mobius Capital Partners after more than three decades at Franklin Templeton Investments. “But that whole story is up in the air in this case.”

This article was provided by Bloomberg News.