Taiwan’s Ministry of Economic Affairs vowed to investigate whether a number of domestic companies involved in the construction of chipmaking facilities for Huawei on the mainland breached expanded US sanctions, Bloomberg reported.

A legislator requested a preliminary report within a month, the news agency wrote.

In addition to looking into export control violations, a ministry representative stated a team will investigate whether the companies’ operations in the mainland are covered in their applications approved by the government.

Minister of Economic Affairs Wang Mei-hua noted the four companies accused of supporting Huawei-affiliated chip plants in Shenzhen are working on waste water and environmental projects, which are not technologies restricted by the Taiwanese government for China.

Bloomberg reported in August the US Semiconductor Industry Association claimed Huawei was secretly building chip-manufacturing capabilities, with an estimated $30 billion in official funding.

Since Huawei was first hit by US sanctions in 2019, it has beefed up R&D spending to reduce its reliance on imports: in March, founder Ren Zhengfei in March outlined its development of local alternatives to components it no longer can source from the US.

Its latest Mate 60 Pro runs on a locally made chipset, indicating gains in advanced manufacturing in the country at the risk of violating US restrictions.