China's heavily indebted property developer Evergrande Group says its founder and chairman Hui Ka Yan is under investigation over suspected illegal acts. He is believed to have been detained by the authorities.

Evergrande's announcement on Thursday came after the Hong Kong stock exchange said earlier in the day that it had suspended the group's shares from trading.

The company says it expects the suspension to continue for the time being as Hui is being investigated without giving further details.

Evergrande descended into a financial crisis due to tightened government regulations and other factors.

The group filed for US bankruptcy protection in August, but postponed negotiations with creditors over debt restructuring.

Evergrande also announced earlier this week that it had missed a deadline for the repayment of principal and interest on a yuan-denominated bond.

Multiple former executives of the group, including ex-CEO Xia Haijun, have reportedly also been detained by the authorities.