WASHINGTON (Reuters) - The chair of a U.S. congressional panel wrote to Alphabet's GOOGL.O Google and to Apple AAPL.O on Friday to ask what if any disclosures mobile apps are required to make regarding overseas ties, a concern that follows reports of Chinese investment in popular apps such as TikTok and Grindr.

FILE PHOTO: Tik Tok logos are seen on smartphones in front of a displayed ByteDance logo in this illustration taken November 27, 2019. REUTERS/Dado Ruvic/Illustration

Rep. Stephen Lynch, chairman of a subcommittee of the House of Representatives Oversight Committee, said in a statement that he had asked both Google and Apple to tell Congress whether they required app developers to disclose any non-U.S. ties.

Concern over China acquiring sensitive data about U.S. citizens through social media apps is one of several sore areas in relations between the United States and China even as U.S. President Donald Trump’s trade war with China fans suspicion between the world’s two largest economies.

TikTok, which is wildly popular with teenagers, is owned by Chinese technology company ByteDance. In a related matter, the Chinese gaming company Beijing Kunlun Tech Co Ltd has said it would sell popular gay dating app Grindr Inc by June 2020 because of U.S. national security concerns.

“Recent press reports have shed light on allegations that certain foreign companies and developers may be providing sensitive data on U.S. citizens via their mobile applications to their host governments, thereby creating significant national security risks,” Lynch wrote in similar letters to Google chief executive Sundar Pichai and Apple’s Tim Cook.

“U.S. laws permit mobile applications to collect massive amounts of personal information about their users,” the letters said, noting that some of the data is sensitive.

Neither Apple nor Google responded to requests for comment.

Because of concern about TikTok, which is under scrutiny from the interagency Committee on Foreign Investment in the United States (CFIUS), ByteDance has stepped up efforts to separate the app from much of its Chinese operations.

CFIUS has sought assurances that personal data held by TikTok is stored securely in the United States and will not be compromised by Chinese authorities.

A senior Democratic committee aide noted an FBI warning that apps developed by adversaries such as Russia were potential counterintelligence threats. “It’s worth asking whether Russia and China might be manipulating popular applications to gain a national security advantage,” the aide said.