The Korea Communications Commission will look into whether app market operators -- Apple, Google and One Store -- are in violation of a Korean law that bans forcing certain in-app payment methods among app developers, the regulatory agency said Tuesday.

The fact-checking investigation will begin from Aug. 16, according to the KCC. App market operators that only allow certain payment options or refuse app registrations or updates of app developers that use external links for in-app purchases could be deemed as a violation of the Telecommunications Business Act, the agency said.

“If the results of the investigation are judged to be a violation, like forcing a specific payment method, we plan to take strict measures such as issuing corrective orders or imposing fines,” the KCC said in a statement.

The KCC has conducted conditional inspections of the three app market operators since May 17 after it received complaints that Google forced app developers to use its own in-app payment system, which takes 15 to 30 percent commission from transactions, and removed external payment options.

Last month, Kakao ended up removing the external payment link for its messenger app KakaoTalk after Google rejected the Korean company’s request for the latest software update.

Local app developers in music streaming, webtoon and digital books have blamed Google’s new in-app payment policy as the reason behind the recent price hikes in their content.