Chinese authorities said on Monday they had executed four people convicted of causing the deaths of six Chinese nationals and running fraud and gambling operations in Myanmar worth more than $4 billion.

The Shenzhen Intermediate People’s Court in southern China said in a statement issued on Monday morning that the death sentences had been carried out, without specifying the date of execution.

The move follows the execution last week of 11 other people convicted of running fraud operations linked to Myanmar.

In November, the same court sentenced five people to death, including members of the notorious Bai family, for operating a network of scam centres and gambling clubs, the Associated Press reported.

China has stepped up its crackdown on cross-border fraud networks in recent years, particularly those operating in Southeast Asia and targeting Chinese citizens.