Officials said in May they were investigating the shipment of "high-end" artificial intelligence servers containing advanced Nvidia chips to China, Macau and Hong Kong, in violation of US export controls.

And on Monday investigators raided the homes of six people and offices of Nasdaq-listed Super Micro as well as Taiwan-listed Albatron Technology and Chief Telecom.

Huang Sheng, head prosecutor in the Keelung Prosecutors Office, said on Thursday that two Super Micro workers had been detained, while two others were released on bail.

Nine people were now under investigation, while six people had been held, including two from Super Micron and one from Albatron, he said.

They are accused of forging documents to ship roughly 50 servers made by Super Micro Computer to China.

Some of the servers were cleared by Taiwan customs and sent to China via Japan, an official previously told AFP on the condition of anonymity.

The Super Micro workers who had been detained were senior staff members from the sales department, while the person from Albatron was a senior manager, Huang said.

Super Micro said in a statement on Wednesday that it was not "a target of this investigation", and that it had been providing information and working with the authorities for several months.

"Super Micro remains committed to protect US interests and to safeguarding our advanced technologies," it said.

Taiwan prosecutors say it is too early to know if the case is linked to a Nvidia chip smuggling case involving Super Micro Computer employees in the United States and Singapore.

Singapore police seized a luxury bungalow on Wednesday worth more than US$40 million as part of fraud investigations linked to the alleged transfer of AI chips.

A US indictment unsealed in March showed employees of the company allegedly raked in billions of dollars diverting Nvidia AI chips to China in breach of export controls.