TOKYO -- Japan's Financial Services Agency has started to raid more operators of virtual currency exchanges in the country to check that they have adequate security monitoring systems, Finance Minister and Deputy Prime Minister Taro Aso told reporters on Friday.

This follows the massive hack of Tokyo cryptocurrency exchange Coincheck in which 58 billion yen ($532 million) worth of NEM virtual currency was stolen on Jan. 26. The financial watchdog on Feb. 1 asked all cryptocurrency exchange operators to report their security measures to control risks to their systems by the following day. 

Based on the results of the survey, the authorities decided to raid more operators, Aso explained. The FSA performed an on-site inspection of Coincheck on Feb. 2.