Taiwan will investigate whether Taiwanese firms helping Huawei Technologies with chipmaking plants in China violated U.S. sanctions, ramping up scrutiny of a company at the heart of Washington-Beijing tensions over technology.

Minister of Economic Affairs Wang Mei-hua told lawmakers on Wednesday that her agency has agreed to launch a probe into that unusual relationship. She was responding to a request by ruling Democratic Progressive Party lawmaker Lai Jui-lung during a legislative session that followed a Bloomberg News report this week identifying four firms working on chip plants backed by Huawei in China. Lai asked for a preliminary report on the probe within a month.

The local Central News Agency also cited an unidentified Economic Affairs ministry official saying its investment department will look into whether the firms are conducting their businesses in China within the scope of an original application approved by Taipei.