WASHINGTON, July 21 (Reuters) - Three Republican House lawmakers on Monday asked the CEOs of Alphabet GOOGL.O, Facebook-parent Meta META.O, Amazon.com AMZN.O and Microsoft MSFT.O if the tech firms have adopted adequate safeguards to address growing concerns about China and Russia on submarine communications cables.

Washington has been raising alarm about the network of more than 400 subsea cables that handle 99% of international internet traffic. The letter signed by Representative John Moolenaar, who chairs a House panel on China and two other Republicans, raised concerns that entities affiliated with China "such as SBSS, Huawei Marine, China Telecom, and China Unicom, have continued to provide maintenance or servicing to cable systems in which your companies maintain direct or indirect operational involvement or ownership."

(Reporting by David Shepardson, Editing by Franklin Paul)

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