Chinese regulators have advised financial institutions to curb holdings of U.S. Treasuries due to concern over concentration risk and market volatility, Bloomberg News reported on Monday, citing people familiar with the matter.

Officials urged banks to limit purchases of U.S. government bonds and instructed those with high exposure to pare down positions, though the advisory does not apply to state holdings, Bloomberg reported.

The People's Bank of China and National Financial Regulatory Administration did not immediately respond to Reuters' requests for comment.

The advisory was framed as an effort to diversify market risk rather than a response to geopolitical maneuvering or a loss of confidence in U.S. creditworthiness, Bloomberg reported.

The guidance came before President Xi Jinping held a telephone call with U.S. President Donald Trump last week, Bloomberg said.

Trump's unpredictable approach to trade and diplomacy, his attacks on the Federal Reserve and huge increases in public spending has left market participants questioning the haven status of U.S. debt.