BEIJING - China's foreign exchange regulator said Monday it has teamed up with the public security ministry to fight forex-related irregularities, with nearly a hundred cases of underground bank trading cracked in 2017.

These cases involved a total value of hundreds of billions of yuan, the State Administration of Foreign Exchange (SAFE) said.

The SAFE said it will continue to work with the police to further investigate underground banking this year to protect China's economic and financial security.

Both those running underground banks and those participating in such trading will be punished, the regulator said, promising that the two departments will enhance information exchange and situation analysis to intensify the fight against illegal forex trading.

While financial innovation should be supported, regulators will maintain a tough stance on forex-related crime and irregularities in the name of innovation, the SAFE said.

China saw stable and balanced cross-border capital flow and transactions in 2017. At the end of December, the country's foreign exchange reserves rose for the 11th month in a row to $3.14 trillion.