The attack on U.S. tech companies continues with the Japanese government set to start investigating how Apple Inc. and Alphabet Inc.’s Google deal with Japanese smartphone makers, which could lead to the tightening of antitrust regulations, According to The Japan Times using the Nikkei newspaper as its sole source.

A government panel, which consists of officials, bureaucrats and external experts, will kick off the discussion this month as Apple’s iOS and Google’s Android software stands at more than 90% of the Japanese smartphone market, the paper said. The probe will include input from executives from domestic smartphone handset-makers as well as manufacturers of smart speakers and personal computers.

The panel will evaluate business dealings in Japan and whether they are conducted in a fair manner compared with cases overseas. The government may step up antitrust regulations if the panel finds any issues from the probe.

The news caps off a week where Silicon Valley's big four were under attack. Below are three reports that Patently Apple posted this week:

01: EU Competition Chief Vestager all but confirmed that Apple will be forced to allow a Second App Store on its Platform

02: The attack on big tech continues with Amazon & Google Execs set to Testify before the Senate's Antitrust Subcommittee next week

03: The U.S. House of Representatives is working to introduce Five Antitrust Bills in the next week that will Squarely affect Apple and its App Store