The Taiwanese government has launched an investigation into four firms suspected of cooperating with the Chinese company Huawei, reports Reuters.

According to media reports, several Taiwanese tech companies are helping Huawei build infrastructure for a secret network of chip factories in southern China.

The targeted companies include divisions of Topco Scientific Co., L&K Engineering Co. and United Integrated Services Co. as well as Cica-Huntek Chemical Technology Taiwan Co.

Now, the Ministry of Economic Affairs of Taiwan will examine whether their activities in China comply with investment permits issued by the island’s government.

“If not, then the highest permitted fine is up to T$25 million ($775,300),” said Taiwan’s Minister of Economy Wang Mei-hua.

As you know, the Chinese company Huawei is under US sanctions. The potential cooperation of Taiwanese companies with it raises many questions, in particular because China regularly threatens Taiwan with military action.