Apple Inc. removed more than 30,000 apps from its China store Saturday, with games making up 90% of the apps, Qimai Research Institute said.

The peak of the removals took place at 4:15 a.m. local time, when more than 2,000 apps were deleted, the Chinese research firm said. The bulk of the removals were done between 3 a.m. and 5 a.m., it added.

About 179,000 game apps remained in the China store as of Saturday evening, of which about 160,000 were offered for free, it said.

Apple (AAPL) sent a reminder to game developers July 8 about its plans for the removal if they didn’t meet regulatory requirements for payments by the end of the month, Qimai said, citing an email from the iPhone maker.